Here's a simplified view of the process. Actually once I got into it I forgot to save out the steps. But this is the first (the sketch), second (laying down a base tone), and third (start shading using the sketch as guidelines). Basically I continue step three (with my brushes flow set to 3-5) until the sketch begins to get in the way then I turn it off and finish the face. I'll turn the sketch back on to do the hair. I usually do the hair and/or the eyes last.