My theory of characterization is basically this: Put some dirt on a hero, and put some sunshine on the villain, one brush stroke of beauty on the villain.
One thing that worried me was how writers get categorized and so they end up having to write the same kind of book again and again. That is fine if it is what you want to do, but I would rather be locked in the trunk of my car with a weasel than write the same book every three years until I die.
I tend to start at 9 o'clock in the morning and write until 3. Those are my best hours. They fit the other rhythms of the world. So I write for six hours, pretty much without any breaks.