I'll comment on things that I have been researching and concentrating on lately. The more I read, the more often these fundamentals are overlooked or not understood. Hell, I didn't know until recently as I am trying to do more 'people' shots.
#1 - Nice example of a full face mask. I think either your camera position is slightly high or your model was lookig at you rather than the lens. This is causing too much wjites of her eyes to be showing and not enough iris. Her shoulder being rolled forward has caused several issues I think. 1) an imbalance in her stance 2) slouching posture 3) her shoulder being more prominent than her face and 4) a little extra tummy roll. Her left hand and knee are even more prominent in their positions. Lastly, the jewelry doesn't play well.
#2 - Very nice example of a 2/3rds and a profile mask in the same shot. This would have given a nice interplay between them if only one was looking at the other. I think you're getting some wrap around reflection off the background. Did you use a flag or any other modifier?
#3 - Sorry, but this one doesn't work for me. Girl on right doesn't have the right stuff to pull that pose off.... at least not in those shorts. She looks very uncomfortable. Girl on left, not so bad. However there is a flash running across her chest.
#4 - Girl on left needs a cell phone in her hand. Girl on right needs to be removed.
The background on all of them look bad with (guessing) clean up in post. There is an awful lot of swoops and swirls and some color shift.
Sorry if that sounds negative, but it isn't in the overall. Still nice shots. Thanks for sharing.