That's looking good. You might also try changing the hilight color and % on the skin, and the reflection color. The hair looks fantastic. You can use the same picture you have in the bacground as a reflection map too. Apply it to somthing shiny such as a wide bracelet. It really helps a lot to integrate your figure with the background.

"Your work is to keep cranking the flywheel that turns the gears that spin the belt in the engine of belief that keeps you and your desk in midair."

Annie Dillard