Many nights start like this: I sit in front of the computer and stare at a blank canvas and wonder what I'll draw. Sometimes I store an idea during the day on a scrap of paper--more regularly I have an idea but forget to write it down, which is the same as having no ideas. Most days I start drawing the Little Guy and hope for inspiration.
Once I have an idea, I either draw from memory if it's simple, or check sewcrates's photo page, or search various image searches for a model. I then start doodling away.
On the good days, I'll end up with something I'm proud of. On the normal days, I'll have something passable. And on the terrible days I'll question why I bother. As I was telling Jennifer yesterday, in my view, art is all about repetition until your fingers bleed in the hopes of creating something worthwhile.