Figure out what service you are currently buying from somebody where.. something pisses you off and you figure you can do it better, a niche, something you are passionate about, a new focus (value layer abstraction), a new category, where you can be a leader, maybe a bit geeky.. but ready for general adoption, something that allows you to take a bit of risk (ahead of the cure).
I’ve kinda done the above 3 times already.
It helps if people tell you it can’t be done. Good motivation.
Another way to read this: Your customers are your future competition.