(This essay is derived from a guest lecture in Sam Altman's startup class at Stanford. It's intended for college students, but much of it is applicable to potential founders at other ages.)
One of the advantages of having kids is that when you have to give advice, you can ask yourself "what would I tell my own kids?" My kids are little, but I can imagine what I'd tell them about startups if they were in college, and that's what I'm going to tell you.
Startups are very counterintuitive. I'm not sure why. Maybe it's just because knowledge about them hasn't permeated our culture yet. But whatever the reason, starting a startup is a task where you can't always trust your instincts.
It's like skiing in that way. When you first try skiing and you want to slow down, your instinct is to lean back. But if you lean back on skis you fly down the hill out of control. So part of learning to ski is learning to suppress that impulse. Eventually you get new habits, but at first it takes a conscious effort. At first there's a list of things you're trying to remember as you start down the hill.
Startups are as unnatural as skiing, so there's a similar list for startups. Here I'm going to give you the first part of it—the things to remember if you want to prepare yourself to start a startup.
The first item on it is the fact I already mentioned: that startups are so weird that if you trust your instincts, you'll make a lot of mistakes. If you know nothing more than this, you may at least pause before making them.
When I was running Y Combinator I used to joke that our function was to tell founders things they would ignore. It's really true. Batch after batch, the YC partners warn founders about mistakes they're about to make, and the founders ignore them, and then come back a year later and say "I wish we'd listened."
Why do the founders ignore the partners' advice? Well, that's the thing about counterintuitive ideas: they contradict your intuitions. They seem wrong. So of course your first impulse is to disregard them. And in fact my joking description is not merely the curse of Y Combinator but part of its raison d'etre. If founders' instincts already gave them the right answers, they wouldn't need us. You only need other people to give you advice that surprises you. That's why there are a lot of ski instructors and not many running instructors. 
You can, however, trust your instincts about people. And in fact one of the most common mistakes young founders make is not to do that enough. They get involved with people who seem impressive, but about whom they feel some misgivings personally. Later when things blow up they say "I knew there was something off about him, but I ignored it because he seemed so impressive."
If you're thinking about getting involved with someone—as a cofounder, an employee, an investor, or an acquirer—and you have misgivings about them, trust your gut. If someone seems slippery, or bogus, or a jerk, don't ignore it.
This is one case where it pays to be self-indulgent. Work with people you genuinely like, and you've known long enough to be sure.
The second counterintuitive point is that it's not that important to know a lot about startups. The way to succeed in a startup is not to be an expert on startups, but to be an expert on your users and the problem you're solving for them. Mark Zuckerberg didn't succeed because he was an expert on startups. He succeeded despite being a complete noob at startups, because he understood his users really well.
If you don't know anything about, say, how to raise an angel round, don't feel bad on that account. That sort of thing you can learn when you need to, and forget after you've done it.
In fact, I worry it's not merely unnecessary to learn in great detail about the mechanics of startups, but possibly somewhat dangerous. If I met an undergrad who knew all about convertible notes and employee agreements and (God forbid) class FF stock, I wouldn't think "here is someone who is way ahead of their peers." It would set off alarms. Because another of the characteristic mistakes of young founders is to go through the motions of starting a startup. They make up some plausible-sounding idea, raise money at a good valuation, rent a cool office, hire a bunch of people. From the outside that seems like what startups do. But the next step after rent a cool office and hire a bunch of people is: gradually realize how completely fucked they are, because while imitating all the outward forms of a startup they have neglected the one thing that's actually essential: making something people want.
We saw this happen so often that we made up a name for it: playing house. Eventually I realized why it was happening. The reason young founders go through the motions of starting a startup is because that's what they've been trained to do for their whole lives up to that point. Think about what you have to do to get into college, for example. Extracurricular activities, check. Even in college classes most of the work is as artificial as running laps.
I'm not attacking the educational system for being this way. There will always be a certain amount of fakeness in the work you do when you're being taught something, and if you measure their performance it's inevitable that people will exploit the difference to the point where much of what you're measuring is artifacts of the fakeness.
I confess I did it myself in college. I found that in a lot of classes there might only be 20 or 30 ideas that were the right shape to make good exam questions. The way I studied for exams in these classes was not (except incidentally) to master the material taught in the class, but to make a list of potential exam questions and work out the answers in advance. When I walked into the final, the main thing I'd be feeling was curiosity about which of my questions would turn up on the exam. It was like a game.
It's not surprising that after being trained for their whole lives to play such games, young founders' first impulse on starting a startup is to try to figure out the tricks for winning at this new game. Since fundraising appears to be the measure of success for startups (another classic noob mistake), they always want to know what the tricks are for convincing investors. We tell them the best way to convince investors is to make a startup that's actually doing well, meaning growing fast, and then simply tell investors so. Then they want to know what the tricks are for growing fast. And we have to tell them the best way to do that is simply to make something people want.
So many of the conversations YC partners have with young founders begin with the founder asking "How do we..." and the partner replying "Just..."
Why do the founders always make things so complicated? The reason, I realized, is that they're looking for the trick.
So this is the third counterintuitive thing to remember about startups: starting a startup is where gaming the system stops working. Gaming the system may continue to work if you go to work for a big company. Depending on how broken the company is, you can succeed by sucking up to the right people, giving the impression of productivity, and so on.  But that doesn't work with startups. There is no boss to trick, only users, and all users care about is whether your product does what they want. Startups are as impersonal as physics. You have to make something people want, and you prosper only to the extent you do.
The dangerous thing is, faking does work to some degree on investors. If you're super good at sounding like you know what you're talking about, you can fool investors for at least one and perhaps even two rounds of funding. But it's not in your interest to. The company is ultimately doomed. All you're doing is wasting your own time riding it down.
So stop looking for the trick. There are tricks in startups, as there are in any domain, but they are an order of magnitude less important than solving the real problem. A founder who knows nothing about fundraising but has made something users love will have an easier time raising money than one who knows every trick in the book but has a flat usage graph. And more importantly, the founder who has made something users love is the one who will go on to succeed after raising the money.
Though in a sense it's bad news in that you're deprived of one of your most powerful weapons, I think it's exciting that gaming the system stops working when you start a startup. It's exciting that there even exist parts of the world where you win by doing good work. Imagine how depressing the world would be if it were all like school and big companies, where you either have to spend a lot of time on bullshit things or lose to people who do.  I would have been delighted if I'd realized in college that there were parts of the real world where gaming the system mattered less than others, and a few where it hardly mattered at all. But there are, and this variation is one of the most important things to consider when you're thinking about your future. How do you win in each type of work, and what would you like to win by doing? 
That brings us to our fourth counterintuitive point: startups are all-consuming. If you start a startup, it will take over your life to a degree you cannot imagine. And if your startup succeeds, it will take over your life for a long time: for several years at the very least, maybe for a decade, maybe for the rest of your working life. So there is a real opportunity cost here.
Larry Page may seem to have an enviable life, but there are aspects of it that are unenviable. Basically at 25 he started running as fast as he could and it must seem to him that he hasn't stopped to catch his breath since. Every day new shit happens in the Google empire that only the CEO can deal with, and he, as CEO, has to deal with it. If he goes on vacation for even a week, a whole week's backlog of shit accumulates. And he has to bear this uncomplainingly, partly because as the company's daddy he can never show fear or weakness, and partly because billionaires get less than zero sympathy if they talk about having difficult lives. Which has the strange side effect that the difficulty of being a successful startup founder is concealed from almost everyone except those who've done it.
Y Combinator has now funded several companies that can be called big successes, and in every single case the founders say the same thing. It never gets any easier. The nature of the problems change. You're worrying about construction delays at your London office instead of the broken air conditioner in your studio apartment. But the total volume of worry never decreases; if anything it increases.
Starting a successful startup is similar to having kids in that it's like a button you push that changes your life irrevocably. And while it's truly wonderful having kids, there are a lot of things that are easier to do before you have them than after. Many of which will make you a better parent when you do have kids. And since you can delay pushing the button for a while, most people in rich countries do.
Yet when it comes to startups, a lot of people seem to think they're supposed to start them while they're still in college. Are you crazy? And what are the universities thinking? They go out of their way to ensure their students are well supplied with contraceptives, and yet they're setting up entrepreneurship programs and startup incubators left and right.
To be fair, the universities have their hand forced here. A lot of incoming students are interested in startups. Universities are, at least de facto, expected to prepare them for their careers. So students who want to start startups hope universities can teach them about startups. And whether universities can do this or not, there's some pressure to claim they can, lest they lose applicants to other universities that do.
Can universities teach students about startups? Yes and no. They can teach students about startups, but as I explained before, this is not what you need to know. What you need to learn about are the needs of your own users, and you can't do that until you actually start the company.  So starting a startup is intrinsically something you can only really learn by doing it. And it's impossible to do that in college, for the reason I just explained: startups take over your life. You can't start a startup for real as a student, because if you start a startup for real you're not a student anymore. You may be nominally a student for a bit, but you won't even be that for long. 
Given this dichotomy, which of the two paths should you take? Be a real student and not start a startup, or start a real startup and not be a student? I can answer that one for you. Do not start a startup in college. How to start a startup is just a subset of a bigger problem you're trying to solve: how to have a good life. And though starting a startup can be part of a good life for a lot of ambitious people, age 20 is not the optimal time to do it. Starting a startup is like a brutally fast depth-first search. Most people should still be searching breadth-first at 20.
You can do things in your early 20s that you can't do as well before or after, like plunge deeply into projects on a whim and travel super cheaply with no sense of a deadline. For unambitious people, this sort of thing is the dreaded "failure to launch," but for the ambitious ones it can be an incomparably valuable sort of exploration. If you start a startup at 20 and you're sufficiently successful, you'll never get to do it. 
Mark Zuckerberg will never get to bum around a foreign country. He can do other things most people can't, like charter jets to fly him to foreign countries. But success has taken a lot of the serendipity out of his life. Facebook is running him as much as he's running Facebook. And while it can be very cool to be in the grip of a project you consider your life's work, there are advantages to serendipity too, especially early in life. Among other things it gives you more options to choose your life's work from.
There's not even a tradeoff here. You're not sacrificing anything if you forgo starting a startup at 20, because you're more likely to succeed if you wait. In the unlikely case that you're 20 and one of your side projects takes off like Facebook did, you'll face a choice of running with it or not, and it may be reasonable to run with it. But the usual way startups take off is for the founders to make them take off, and it's gratuitously stupid to do that at 20.
Should you do it at any age? I realize I've made startups sound pretty hard. If I haven't, let me try again: starting a startup is really hard. What if it's too hard? How can you tell if you're up to this challenge?
The answer is the fifth counterintuitive point: you can't tell. Your life so far may have given you some idea what your prospects might be if you tried to become a mathematician, or a professional football player. But unless you've had a very strange life you haven't done much that was like being a startup founder. Starting a startup will change you a lot. So what you're trying to estimate is not just what you are, but what you could grow into, and who can do that?
For the past 9 years it was my job to predict whether people would have what it took to start successful startups. It was easy to tell how smart they were, and most people reading this will be over that threshold. The hard part was predicting how
A lot of the advice we give startups is tactical; meant to be helpful on a day to day or week to week basis. But some advice is more fundamental. We’ve collected here what we at YC consider the most important, most transformative advice for startups. Whether common sense or counter-intuitive, the guidance below will help most startups find their path to success.
The first thing we always tell founders is to launch their product right away; for the simple reason that this is the only way to fully understand customers’ problems and whether the product meets their needs. Surprisingly, launching a mediocre product as soon as possible, and then talking to customers and iterating, is much better than waiting to build the “perfect” product. This is true as long as the product contains a “quantum of utility” for customers whose value overwhelms problems any warts might present.
Once launched, we suggest founders do things that don’t scale (Do Things That Don’t Scale by Paul Graham). Many startup advisors persuade startups to scale way too early. This will require the building of technology and processes to support that scaling, which, if premature, will be a waste of time and effort. This strategy often leads to failure and even startup death. Rather, we tell startups to get their first customer by any means necessary, even by manual work that couldn’t be managed for more than ten, much less 100 or 1000 customers. At this stage, founders are still trying to figure out what needs to be built and the best way to do that is talk directly to customers. For example, the Airbnb founders originally offered to “professionally” photograph the homes and apartments of their earliest customers in order to make their listings more attractive to renters. Then, they went and took the photographs themselves. The listings on their site improved, conversions improved, and they had amazing conversations with their customers. This was entirely unscalable, yet proved essential in learning how to build a vibrant marketplace.
Talking to users usually yields a long, complicated list of features to build. One piece of advice that YC partner Paul Buchheit (PB) always gives in this case is to look for the “90/10 solution”. That is, look for a way in which you can accomplish 90% of what you want with only 10% of the work/effort/time. If you search hard for it, there is almost always a 90/10 solution available. Most importantly, a 90% solution to a real customer problem which is available right away, is much better than a 100% solution that takes ages to build.
As companies begin to grow there are often tons of potential distractions. Conferences, dinners, meeting with venture capitalists or large company corporate development types (Don’t Talk to Corp Dev by Paul Graham), chasing after press coverage and so on. (YC co-founder Jessica Livingston created a pretty comprehensive list of the wrong things on which to focus [How Not To Fail by Jessica Livingston .]) We always remind founders not to lose sight that the most important tasks for an early stage company are to write code and talk to users. For any company, software or otherwise, this means that in order to make something people want: you must launch something, talk to your users to see if it serves their needs, and then take their feedback and iterate. These tasks should occupy almost all of your time/focus. For great companies this cycle never ends. Similarly, as your company evolves there will be many times where founders are forced to choose between multiple directions for their company. Sam Altman always points out that it is nearly always better to take the more ambitious path. It is actually extraordinary how often founders manage to avoid tackling these sorts of problems and focus on other things. Sam calls this “fake work”, because it tends to be more fun than real work (The Post YC Slump by Sam Altman).
When it comes to customers most founders don’t realize that they get to choose customers as much as customers get to choose them. We often say that a small group of customers who love you is better than a large group who kind of like you. In other words, recruiting 10 customers who have a burning problem is much better than 1000 customers who have a passing annoyance. It is easy to make mistakes when choosing your customers so sometimes it’s also critical for startups to fire their customers. Some customers can cost way more than they provide in either revenue or learning. For example, Justin.tv/Twitch only became a breakout success when they focused their efforts toward video game broadcasters and away from people trying to stream copy written content (Users You Don’t Want by Michael Seibel.)
Growth is always a focus for startups, since a startup without growth is usually a failure. However, how and when to grow is often misunderstood. YC is sometimes criticised for pushing companies to grow at all costs, but in fact we push companies to talk to their users, build what they want, and iterate quickly. Growth is a natural result of doing these three things successfully. Yet, growth is not always the right choice. If you have not yet made something your customers want – in other words, have found product market fit, it makes little sense to grow (The Real Product Market Fit by Michael Seibel). Poor retention is always the result. Also, if you have an unprofitable product, growth merely drains cash from the company. As PB likes to say, it never makes sense to take 80 cents from a customer and then hand them a dollar back. The fact that unit economics really matter shouldn’t come as a surprise, but too many startups seem to forget this basic fact (Unit Economics by Sam Altman).
Startup founders’ intuition will always be to do more whereas usually the best strategy is almost always to do less, really well. For example, founders are frequently tempted to chase big deals with large companies which represent amazing, company validating relationships. However, deals between large companies and tiny startups seldom end well for the startup. They take too long, cost too much, and often fail completely. One of the hardest things about doing a startup is choosing what to do, since you will always have an infinite list of things that could be done (Startup Priorities by Geoff Ralston). It is vital that very early a startup choose the one or two key metrics it will use to measure success, then founders should choose what to do based nearly exclusively on how the task will impact those metrics. When your early stage product isn’t working it’s often tempting to immediately build new features in order to solve every problem the customer seems to have instead of talking to the customer and focusing only on the most acute problem they have.
Founders often find it surprising to hear that they shouldn’t worry if their company seems badly broken. It turns out that nearly every startup has deep, fundamental issues, even those that will end up being billion dollar companies. Success is not determined by whether you are broken at the beginning, but rather what the founders do about the inevitable problems. Your job as a founder will often seem to be continuously righting a capsized ship. This is normal.
It is very difficult as a new startup founder not to obsess about competition, actual and potential. It turns out that spending any time worrying about your competitors is nearly always a very bad idea. We like to say that startup companies always die of suicide not murder. There will come a time when competitive dynamics are intensely important to the success or failure of your company, but it is highly unlikely to be true in the first year or two.
A few words on fundraising (A Guide to Seed Fundraising by Geoff Ralston). The first, best bit of advice is to raise money as quickly as possible and then get back to work. It is often easy to actually see when a company is fundraising by looking at their growth curve and when it flattens out they are raising money. Equally important is to understand that valuation is not equal to success or even probability of success (Fundraising Rounds are not Milestones by Michael Seibel). Some of Y Combinator’s very best companies raised on tiny initial valuations (Airbnb, Dropbox, Twitch, are all good examples). By the way, it is vital to remember that the money you raise IS NOT your money. You have a fiduciary and ethical/moral duty to spend the money only to improve the prospects of your company.
It is also important to stay sane during the inevitable craziness of startup life. So we always tell founders to make sure they take breaks, spend time with friends and family, get enough sleep and exercise in between bouts of extraordinarily intense, focused work. Lastly, a brief word on failure. It turns out most companies fail fast because founders fall out. The relationships with your cofounders matter more than you think and open, honest communications between founders makes future debacles much less likely. In fact, it turns out that one of the best things you can do to make your startup successful, in fact, to be successful in life, is to simply be nice (Mean People Fail by Paul Graham.)
The Pocket Guide of Essential YC Advice
• Launch now
• Build something people want
• Do things that don’t scale
• Find the 90 / 10 solution
• Find 10-100 customers who love your product
• All startups are badly broken at some point
• Write code – talk to users
• “It’s not your money”
• Growth is the result of a great product not the precursor
• Don’t scale your team/product until you have built something people want
• Valuation is not equal to success or even probability of success
• Avoid long negotiated deals with big customers if you can
• Avoid big company corporate development queries – they will only waste time
• Avoid conferences unless they are the best way to get customers
• Pre-product market fit – do things that don’t scale: remain small/nimble
• Startups can only solve one problem well at any given time
• Founder relationships matter more than you think
• Sometimes you need to fire your customers (they might be killing you)
• Ignore your competitors, you will more likely die of suicide than murder
• Most companies don’t die because they run out of money
• Be nice! Or at least don’t be a jerk
• Get sleep and exercise – take care of yourself
Do Things That Don’t Scale by Paul Graham ↩
Don’t Talk to Corp Dev by Paul Graham ↩
How Not To Fail by Jessica Livingston ↩
The Post YC Slump by Sam Altman ↩
Users You Don’t Want by Michael Seibel ↩
The Real Product Market Fit by Michael Seibel ↩
Unit Economics by Sam Altman ↩
Startup Priorities by Geoff Ralston ↩
A Guide to Seed Fundraising by Geoff Ralston. ↩
Fundraising Rounds are not Milestones by Michael Seibel ↩
Mean People Fail by Paul Graham ↩
1.A Fundraising Survival Guide by Paul Graham
2.How to Raise Money by Paul Graham
3.Taking Advice by Aaron Harris