It looks like this was a fun shoot, this model looks like she really got into it.
1) This combination of lighting and post processing makes the background look funky, almost like it was shot on a plain white background and then the bricks were added in post just to break up the white space. (Or is that really the case?) I like that you used props (throughout these shots), I just have two problems with the phone in this particular shot. The key thing about this phone is the quirky banana handset, but you can barely see it because of her hand position and because she's holding it up to the ear that is turned away from the camera. It also bugs me a little bit that you can see the empty phone cord socket on the side of the phone. Of course the phone isn't plugged in, but I bet that fact wouldn't stand out so much if you clone out that socket (or had shot the other side of the phone). Also, did you rotate this image? The line at the bottom left is distracting.
2) I really like the quirkiness of this shot. Great expression, nice timing on the bubble. I like the "single safety pin as earring" idea, but I don't think it really works here - the head-on orientation, combined with the bubble, hide it a bit too much and it gives the image an unbalanced feel (everything else is pretty symmetric). Minor point - I would have liked to see the hot spot on the background more centered rather than over her right shoulder...again, it goes to the symmetry of the shot. On the plus side, I really like that you went with a non-standard crop ratio, letting the image dictate the cropping rather than forcing it.
3) On okay shot but in my opinion probably the weakest of the set. The lighting is uneven...I'm seeing hot spots on her face (beside her right eye) and on the guitar, yet in the bottom left corner she fades into the shadows.
4) I like the energy in this shot, and it's a great pose. I like that her head and torso are off center, but because of the right hook her arms are covering the width pretty equally. I like that you even caught one earring square to the camera. I like where you've cropped it vertically (both top and bottom) - I went back and forth on whether I liked her right arm getting cropped or if I'd prefer it to all be in the frame, but I think it might work better this way. I do think the horizontal cropping could be a bit more even - I don't like how close her left hand is to the edge of the frame.
5) Nice concept, nice pose (I like that her hip is cocked and her left leg is kicked out, giving her body some angles). I'll admit that I don't often care for tilted photos and this is a good example of why not. When you have a horizon (in this case, a virtual horizon as the floor meets the wall), a tilt just looks off - here she looks like she's on the deck of a ship listing about 40 degrees (it's probably going to go under with the next good wave). I would have like to see your lighting cranked up more, to get some more detail in her back against that brilliant exterior light (and to not lose her feet in the shadows). I would have recommended moving her to one side or the other so that the window frame wasn't coming right out of her head. And finally (nitpicking a bit), I would have slung the guitar the other way, with the neck down (if you take a guitar in a playable position like in shot 3 and throw it over a shoulder, it will be upside down on your back).