Hmmm... I think with her colouring a darker background would have worked better. The lighting on the subject isn't bad, but because she's very fair-skinned and with her red hair, the images seem a bit washed out. A few minor nits: Watch the details such as the bikini tie in #1; that really kills the image. Have the model vary her expression; these should be happy shots, and when posing as in #3, ensure that the model doesn't compress her flesh with her hand arm, it tends to give things an odd shape, and also don't forget to keep your studio lights up so that the model's pupils don't dilate unnaturally.