This is as much for my own reference as anyone else's, because I do full-on digital paint so rarely that I forget exactly how I did it the previous time.
Incidentally, the first time I used this method of painting was also on a picture of Vaughn and his sister. Only, y'know, the other one. http://www.furaffinity.net/view/7912694/
Link
KyleWilliam
Wow.