I started off by drawing 9 different ladies (in order to utilize all of the paper space I was using, then when I went to color them I couldn't decide how I wanted to. So I took those 9 and made 8 copies giving me 9 ATCs of EACH lady.
I then just grabbed markers from one stack, used them on a gal and put them into another stack. When I went through all the colors I started over again so it gave quite a combination of skin tones and hair colors.
Watchout! If you sign up for any of the "send 10 ATCs or random ATC" swaps on swap-bot, chances are, you'll get one of these ladies.