When working from my imagination, I usually start in black and white and then work into color. This time I got brave and I went straight for the color. I started off by drawing the profile with the lasso tool(a mask would be better, I was being a bit lazy.) I used the round soft brush to block in the colors focusing on making the form turn and thinking about how the color temperature and value would be shifting as the form turned, just as if I were drawing a fleshy sphere. I stuck with just the skin color, and I kept the brush as large as I could for as long as I could. This had two benefits. The first is that the edges and colors blended automatically, and second, I didn't get lost in details as soon as I might otherwise, which helped to keep the value masses simple.
After that, I used a rake-like brush and captured oil strokes to define the plains of the face and get sharp edges and a traditional feel.