Before I make that first keystroke on any first draft, my heart afire with hope while my brain is screaming "Seriously? You're doing this again?", I get to know my characters. My logic is the better I know them, the better I can write them. Of course, there are always surprises along the way, but having some basic knowledge of each of them makes the journey a great deal smoother.
Here are some examples of questions:
10. How old are you?
9. Where do you live?
8. Are you shy?
7. What are you most afraid of? (this is wonderful information)
6. Are you good with people?
5. What do you do for a living?
4. How observant are you?
3. Do other people's opinions matter to you?
And the two most important...
2. What do you want?
1. How is that different from what you need?
Why won't you say or do what I want you to do?