The clothing and hair work really well, and I like the overall tonality of the image, plus the plain (but not cold) background really brings out the model's warm tones and colours, so good work on those angles.
I'd have to agree wholeheartedly on the expression she has though, as not only does she not look very comfortable or happy, she actually looks decidedly UNhappy to me!
So I guess the main suggestion I'd make here is about you being in a position (as the photographer) to take more control of such things - remember, even if the model is paying YOU to take the photos, you're still the only one who can see their face/pose/expression etc, and so the responsibilty is on you to suggest changes and alternatives. Unsurprisingly, although some people are naturals, and some people who tout themselves as pro models are actually useless, I tend to find that the less experienced models are sometimes nervous and inexperienced (as you'd expect) and can be too busy worrying about sucking-in their stomach or whatever else to remember to keep the expression and other elements of the pose looking natural and relaxed (if natural and relaxed is what's required).
So, don't be afraid to direct models as you want, and take as long as you need to get it right. Almost anyone (pro or otherwise) in front of the camera will appreciate rather than resent some gentle direction.