The other pic I was working on for my tutorial is kind of on indefinite hold until I figure out what I really want to do with it.
So here is a quickie show of how I color.
All of my work is done in Corel Painter, to whom I am married.
I use tons of layers. The lineart itself can be multiple layers just for characters, props, whatever. When it comes to coloring I do a layer for every color - all placed beneath the lineart layer. I coloring it by hand with the stylus rather than selecting areas and using the paint bucket.
Once I’ve mapped out all of the colors I do some final tweaking with saturation and color shades. Then its time for shading. Most of my shading is simply done with a smooth round pen brush, each on their own layer. Some times I set the layer to multiply and simply adjust the opacity to get the shading I want. Other times I consult some of my color pallets. A general rule for me is that shading should be less saturated than the parent color and also be a shift towards blue or purple. I like cold shadows.
Some areas need airbrushing to get the vague hint at 3d. I just use the digital airbrush for that. The airbrush is also useful for doing highlights. I tend to cheat for highlights and just set the layer to screen and turn the opacity down. Highlights are only for raised areas - pecs, shoulders, cheeks, etc.
The penultimate highlights - my little balls of white, are just haphazardly thrown about at places that seem to look best. This is a technique I stole from Sarath. I just like the glossy, smooth effect it gives skin.
And that is pretty much it. I don’t do much in the way of uniform “light sources.”
Hopefully this was somewhat informative :p