I have one piece of advice for you. Make sure that some of your early failures include other people. Many issues that bring down startups at their core are about people, not technology.
Wise point. I've been in a startup before [PS: As early employee; I can see how things can get even more emotional with founders], and I have seen and participated in spectacular clashes. I have also observed first hand, in not for profit projects, how important is to have the right chemistry in a team.
I have one piece of advice for you. Make sure that some of your early failures include other people. Many issues that bring down startups at their core are about people, not technology.