Quentin Tarantino, when asked what film school he went to, famously said, “I didn’t go to film school, I went to films.” Many of the most successful entrepreneurs took a similar approach, forgoing business school and going straight to business. I did it myself.

In many cases, going direct to business means you can expect to fail–possibly many times–before you ultimately succeed. But it also means that you’re not simply absorbing business in theory, making decisions with imaginary dollars and imaginary employees. Under the right circumstances, you can learn more from a business failure than you can from a business degree.

Of course, the goal is success, and to get there you have to find the major risk points in your business and do everything you can to chip them away. The first lesson–the lesson to keep in mind every day–is to pay attention. You will be bombarded with advice, not just from friends, but from successful business people who have already started companies and sold them for hundreds of millions of dollars. And much of this advice will be contradictory–the entrepreneur who made his money selling enterprise software in Manhattan will tell you to focus on revenue; the west coaster who had a social media smash will tell you to go after users.

So find yourself a mentor you trust, with a strategy that interests you, and go after that strategy with complete concentration. You cannot be all things to all men–you can’t expect to be a big hit as a consumer app and an enterprise software suite. If you’re not sure which way to go, the market won’t like you–and neither will investors.

If an investor passes on your company, you should have learned something from the experience. Most investors are happy to give you advice. So long as you don’t try to change their minds once they’ve made their decision, they’ll give you pointers on why they passed. If they tell you they don’t see the need or understand the problem you’re solving, you may have bad alignment between your vision and what the market actually wants. But much more common investor feedback (especially on the east coast), is while they like the product and understand the problem, they don’t see how you make money.

Either way, you should step back and take a look at your business plan. Many entrepreneurs are inclined to think of a cool idea, imagine how it works in their heads, figure out how to build it, and then decide who their customers are and how much they can charge for it. It’s easy to get sucked into this trap especially if you love invention and innovation (you wouldn’t be an entrepreneur if you didn’t). The correct approach was explained to me by one of my mentors: “Talk to a firm in a large industry, ask them what they do every day that takes longer than it should, and find a way to make that thing simpler.”

That’s a new business in a nutshell: market, problem, product. In that order.