C&C per req:
To be honest, this doesn't do a lot for me (and as a general rule, it's pretty hard to go wrong with scantily-clad, attractive women!).
As mentioned, your background is at least one full stop under-exposed, skin tones maybe 1/2, and the the crop really bothers me. Why cut off that sliver of her left arm? You desparately need some accent lighting on the hair; streaked hair, especially when the dark streaks are as dark as this young lady's, can be a challenge, but you need to get some light on it, and pull some detail out.
WHY that bra? Let's face it; there's nothing sexy about this sort of bra, and between it and her expression, it really looks like you caught her in the act of getting dressed and she's mugging it up for the camera.
I understand (I think) what you were going for, but IMO, this falls short. With hair as long as she has, you could easily lose the bra altogether and with some artful posing, still have a perfectly 'SFW' shot.
She's a good looking model - you need to have still another go at this and really do her (and you) justice!
Just my $00.02 worth - your mileage may vary.
~John