"I can think of several heuristics for generating ideas for startups, but most reduce to this: look at something people are trying to do, and figure out how to do it in a way that doesn't suck."
And there's more:
"And what I discovered was that business was no great mystery. It's not something like physics or medicine that requires extensive study. You just try to get people to pay you for stuff."
via Michael Pollack.
Remember, do business in a way that doesn't suck and try to get people to pay you for stuff.