Go research before you do anything. Research instead of having an idea. Go out and look at different groups of people: see what they're doing online, what they're talking about, and what their needs are. Evaluate those audiences, and get an idea based on what those people need (rather than starting with your own idea that's based on you). Learn what people need: that's the most important thing when you're starting out.
I want to keep building businesses that that help people.
Jarrod Drysdale on Thoughtbot with Ben Orenstein
Jarrod wrote an excellent book called Bootstrapping Design
He emphasizes that the above lesson was learned in Amy Hoy's 30x500 class.