I think I'm the kind of person who would be very difficult to employ - I'm pretty annoying, but driven.

If you're in your early 20s and you're hanging out with a bunch of other people in their early 20s, nobody has a sense of the kinds of problems that real 'workers' run into every day. They're running into a completely different set of problems like 'what's the party going on right now that I should be going to?

Innovation in tech favors the naive and the stubborn. If you are too rational you won't tackle problems that others once failed at.

I think because of the iPhone and the fact that we now have a ubiquitous internet, our creativity in the startup space is 10 times different. Every single industry, every single market, is going to be technology-driven in some way. There's an infinite opportunity for startups because now you can go and solve problems that previously looked like they had nothing to do with technology.

Tip: Take the stodgiest, oldest, slowest moving industry you can find. And build amazing software for it.

Read these 3 books - Crossing the Chasm, Innovators Dilemma and Behind the Cloud.

The only barrier to entry you can create is to consistently build a great product.