C&C per req:
1. I'm assuming this was an ambient light exposure with a bright light image right. Unfortunately, it gives the subject a rather unpleasant appearance; rather "Phantom of the Opera". A diffuse fill-flash centre or image left would have helped greatly.
2. Much better expsoure here; still a bit harsh with the strong light image right. The empty area image left isn't helping. I would suggest cloning out the lights in the background as they're major distractions. Additionally, when posing, don't have elements leading out of the image such as her left arm. I think this image would be much stronger shot in portrait aspect with a tight bust crop.
3. Much more pleasing composition here, however the image is soft, and the subject is looking out of the image. While they don't have to look right down the lens, they should usually be looking in your direction.
4. Nice idea, and this is a case where having the subject not looking at the camera does work, however, the image needs to be levelled, and excess DoF has resulted in a sharp, distracting background.
Just my $00.02 worth - your mileage may vary.
~John