Be obsessed with whatever you believe you’re solving.

When you study the lives of successful entrepreneurs, you might notice that most didn't set out to build a business. They identified an opportunity in the guise of a problem that could be solved with technology of the day. The produced a solution and lots of other people had the same problem and were willing to pay for the solution.

Folks who just want to make a lot of money become stock brokers, merchant bankers or venture capitalists and "invest" other people's money in the efforts of the problem solvers.