A couple of things. One, extreme angles like this are a real challenge. I think it would have been more successful if she's tilted her head back and we got a better angle on her face. Overall, I'd try to have her stretch out on that backdrop to reduce the angle.
On the lighting. We're absolutly losing her hair. She's dark haired on a dark background. If she was at a less extreme angle we'd have some light coming across from the right and highlighting her hair. As it is, her body is blocking any cross light. It would have been an option to move your soft box over to image left so that you had some effective spill on her hair. Hate losing the hair.
Looks like a nice model -- I'm sure it wouldn't be a hardship to re-shoot!