I'm no expert by any means but I'll give you my opinion. (t'is my first attempt at critisising someone elses photos as well!)
1) I like the idea of this one but I think the light is far too harsh on her cheek, possibly intentional but it spoils it for me. Is that black make up under her right eye? It kind of distracts me.
2) Nice relaxed pose and the light is good, possibly could have done with some light being reflected in the eyes and maybe a small bit of back lighting to bring out the top of the head. Lose the black bra strap.
3) I like this one except the sepia tone, but that is my personal preference. I prefer mono. The light has blown out the face as well but doesn't detract from the photo for me.
4) My favourite (sucker for ladies with pony tails

). You need to clean your lens! Nice catch light in the eye. A reflector/white card could have been used to bounce some light back onto her right side of her face and maybe reduce the shadow behind her. Also lose the tags in the bears ears
All the photos are noisy, high iso or post processing?
What camer were you using?