Looks like a good first whack on posing... If you have the time, today and or tonight, creativelive.com is having a free webinar/seminar that should be looping through the night with a very good posing/glamour photographer... perhaps you can take a peek and learn a bit as far as hands, etc... Different people will give different suggestions... some will say "tummy away from the light for more slimming poses", which you did, however other will say to use short lighting (you did broad lighting on the face) gives more flattering facial portraits... Also, the lighting technique you used was a semi rembrandt (triangle under the far side cheek)... While executed good, it doesn't quite do her justice... It's generally seen as a harder, more serious and stand-offish setup... It's good if you want to convey that message, but otherwise... The dark outfit slims her but also loses any shape in her figure which doesn't help either. For my suggestions is for my own personal taste so take it with a pinch of salt... If you want to keep lighting where it is, add a second fill light or bring your reflector camera right closer to outside frame to reduce the contrast in the rembrandt. I would move the light more camera axis but slight off camera left giveing a mix of hollywood/butterfly lighting, but add refector below camera view filling shadows under nose and reducing contrast... If light spills on the background, move subject forward or background back to create separation... a longer lens then can be used... Have her hand instead of resting on her hip, have is snake behind the small of her back which will hide the hand but also add curvature to back waist line and chest line... curvature overall looks best for women... If you want to keep it super low key the figure would look black vs a dark brown background which would give some hint to her figure... but to take it to the next level, add a kicker light 130 degrees camera right (or super big reflector if you have no more lights) that just lights her back... feel free to add flags or whatever so the light just hits her back but doesn't cause flare in the lens or spill on the front of her body.... This light will give just a glimmer of light accenting her body off and away from the background. This shows her shape even more. You can even ask her to kick out her hip slightly camera right and have her arm on that side lay against her hip giving more view of the curves... Just some hints on where to go from here.... Very good start and with a few refinements you can become very very good.