The most successful people I know believe in themselves almost to the point of delusion. I remember when Elon Musk took me on a tour of the SpaceX factory many years ago—the thing that sticks in memory was the look of absolute certainty on his face when he talked about sending large rockets to Mars. I left thinking 'huh, so that's the benchmark for what conviction looks like.'

On self-belief, balanced with self-awareness so it doesn't curdle into self-delusion.

I think the biggest competitive advantage in business—either for a company or for an individual's career—is long-term thinking with a broad view of how different systems in the world are going to come together. In a world where almost no one takes a truly long-term view, the market richly rewards those who do.

You don't want to be in a career where people who have been doing it for two years can be as effective as people who have been doing it for twenty—your rate of learning should always be high. As your career progresses, each unit of work you do should generate more and more results.

At YC, we've often noticed a problem with founders that have spent a lot of time working at Google or Facebook. People have an incredible ability to always match their lifestyle to next year's salary. Keeping your life cheap and flexible for as long as you can is a powerful way to make it easy to take risks.

It's easier to do a hard startup than an easy startup. People want to be part of something exciting and feel that their work matters—if you are making progress on an important problem, you will have a constant tailwind of people wanting to help you.

You get truly rich by owning things that increase rapidly in value—a piece of a business, real estate, natural resources, intellectual property. Almost no one in the history of the Forbes list got there with a salary. Time only scales linearly.

On the difference between earning income and building wealth.

An effective way to build a network is to help people as much as you can. I'm continually surprised how often something good happens to me because of something I did to help a founder ten years ago. When meeting someone new I ask: 'is this person a force of nature?'

Most people are primarily externally driven—they do what they do to impress other people. After you've made enough money to buy whatever you want and gotten enough social status that it stops being fun to get more, internal drive is the only force I know of that will continue to drive you to higher levels of performance.