Judson,
All things considered, this is a pretty ambitious composition. I know it may not seem that way but there is an awful lot that you have asked of yourself. Competing elements of shape, color and negative space.
There is a tendency, I still have to fight this, to compose an all inclusive fully descriptive scene. But if you'll notice, when the really good artist gather together to study their portrait work, all they do is study the head. Portrait painting is about the head first, second and third.
My suggestion would be to create some really good reference photo of just a head and shoulder pose (refer to the photo advice section) or if you're up to it, have a friend pose for you, or both. Then work on nailing down the drawing, the form with light and shadow, and the skin tones. And keep the work close to life size, it will make your efforts so much easier.
I look forward to seeing your next effort.
This is exactly what I'm talking about
:
Chris Sapers recent portrait