So that's how you start out: some rough, broad strikes directly onto the screen?
Sometimes. Well, most times.
Yeah, I just slam the thing with broad brushes and kick it into something half-acceptable. Well, I do that with oils as well.
No pencil sketches? No old-school tools?
Cor. Lots of sketches, but those are more often than not scribbled in my sketchbook to think about a pose or the viewer's angle, to doodle shapes and ideas in, to play around with different pencils and techniques.
If I like a sketch very very much, I scan it and work from it... but for most CG work as well as oils, it's more alla prima, I work the ideas out on the sketches and don't, uh, fuck around too much with detail while starting a new piece.
I also sketch shit on the computer, to play around with colors and whatnot; notice how the grey looks like brown when it's set against an all-blue piece: