I don’t develop my characters in a logical way, i.e. answering a list of questions, writing the character’s full background. I do what Holly Lisle (http://www.hollylisle.com/) suggests — Start to develop your character by giving him a problem, a dramatic need.
“Even if you don’t have the foggiest idea what your story is going to be about yet, you don’t know where it’s going to take place, and you haven’t found anything compelling that you’d like to say to an audience, you can do this. Say “My main character wants _____ more than anything else in the world.”
“A rule of good storytelling is that the protagonist will confront the thing he fears the most and overcome it in order to win the thing he desires the most.”
That’s a good rule. I try to do that, but I don’t always succeed.