Two words: "Light" and "Rim". You put them in the right order!
Depending on the intent of the image (ie modelling, acting, etc), I think this is a good, solid, shot with the exeception of the hair. It blends into the background just a bit too much for my taste; I think looking at her colouring, a light blue to middle-grey or even green background would have worked much better. Her skin seems a bit warm on the periphery of her face, but that should be easily adjusted in post.