If you aren’t familiar with cartoonist Tom Richmond, make yourself familiar. This guy’s work is absolutely amazing. Very much in the style of Mort Drucker from MAD Magazine — only taken to the extreme. Not only is his cartooning & caricature style excellent, but his color work is also phenomenal. Tom graciously has taken the time to outline exactly how he digitally colors his artwork in Photoshop in a juicily-detailed three-post tutorial/how-to series on his cartooning blog.
Tutorials
MAD cartoonist Tom Richmond’s Coloring Tutorial
MAD Magazine cartoonist/caricaturist Tom Richmond has an awesome tutorial on his site about his working methods for getting his line art into finished color works of art.