I've already seen this one, and I think I already mentioned really digging your values. Really, the only thing I can see improving is some contrast in the hair, and a little shadowing on the face. You can probably cheat with a dark pencil and effect some hair fibers. It's a little rough doing fine lines with markers or pens. I really dig that this is traitional, not digital. There's something endearing to the medium -- plus, the originals sell really well.