It seems routine is the key to all creative endeavors. Here's what Michael Lewis has to say:
Is there any time of day you like to write?
I've always written best very early in the morning and very late at night. I write very little in the middle of the day. If I do any work in the middle of the day, it is editing what I've written that morning.
What would your ideal writing day look like?
Left to my own devices, with no family, I'd start writing at seven p.m. and stop at four a.m. That is the way I used to write. I liked to get ahead of everybody. I'd think to myself, "I'm starting tomorrow's workday, tonight!" Late nights are wonderfully tranquil. No phone calls, no interruptions. I like the feeling of knowing that nobody is trying to reach me.
See, even professionals have sloppy schedules. It's a comforting thought.