Col-Erase Pencils
When I was drawing and painting conventionally, the style I worked in involved using pencils, col-erase pencils, and acrylics on illustration board. It went something like this:
I'd transfer my drawing onto the illustration board, and redraw it completely with a regular #2 pencil, being very careful at this point about the line quality. Most of the outline was eventually obscured, but starting with a careful drawing made the rest easier.
Next, I'd shade the drawing using the col-erase pencils. Using, for example, a violet pencil for a red object, Id draw in the core shadows and drop shadows. Then (and this is the nifty part about using the col-erase pencils), I'd smudge the shadows with a q-tip or tortillon or chamois cloth to make them really smooth where they needed to be smooth..
This is about the point that I'd become totally discouraged with the artwork and convinced I should just throw it out. Maybe someday I won't go through this as often, but it seems part of the whole process.
The next step was to lightly fix the drawing with workable fixative. Workable fixative is one of those nasty aerosol can things that you should only use outdoors.
The artwork is actually more than halfway done at this point, but it looks odd. Time to pull out the acrylics.
Acrylic Paints
Acrylic paints are great. If you use a base coat of gesso, you can use acrylics on nearly anything. The only downside to acrylics is that they are permanent once they dry.
The way I used acrylics was to water them down a lot and use them like watercolors, with thin, transparent coats over the pencil drawing.(see above) I prefer the tube paints over the jar paints. The jar paints seem to have more binder and less pigment in them. To speed things up, I would often use a hairdryer. (To dry the wet paint, of course!)
Caran D'Ache Neocolor
I use these for sketching in my sketchbook. They're a nifty tool because you can use them like pastels or watercolors, since they're water soluble. The Neocolor sticks aren't cheap, about a dollar each. But they're smudgeable and portable. Just don't confuse these with the oil based crayon that Caran D'Ache also makes that look very similar.