this is how I do a color image:
1. draw a black & white image using pencils, micron markers and brush (Winsor & Newton ink. thick as blood, but "oh the quality of black.") This is done on bristol board.
2. block in some colors using color inks and brushes.
3. Prismacolor markers next. Working light to dark, unlike guache painting where I like to work dark to light.
4. a touch of guache to make some areas pop a bit.
and that's pretty much it. Here are two jpegs showing off the b&w version and the finished color version. cheers!