Overall these are good shots. I think there are some areas to work on, but overall you should feel confident shooting her friends - particularly if they've seen these shots and like them.
Shot 1) This shot seems a bit soft to me - however, this is just an observation not a critique because I think the feeling works well here. The lighting here is very tricky to work with, and as a result some of the whites seem overexposed (at least on this monitor). You have some of the same issues here that wedding photographers do, trying to capture detail in a white dress while exposing the rest of the frame properly. Particularly if you shot in RAW I'd suggest playing around with exposure levels a bit, and then with dodging/burning. I personally like playing with shadows like you did here - some nice shadow shapes on her chest and arm, and to some extent on her face, it's just tricky to nail.
I like the angled composition, however I would suggest cropping off from the right, almost to her head. As it is you have created a nice line from the bottom left corner toward the upper right, but stopping so far from the corner makes the image seem unfinished. Crop off the right and you line now extends almost to the end of frame (and removes most of the brightly lit grass (which competes with the subject for attention). Cropping would also move her face from almost centered to more of a rule of thirds point.
Her head and eyes are a little too square to her body. You could create a more interesting position by either turning her head toward the camera or tilting it toward her shoulder, or even by keeping her head as is (I like the contours of her 3/4 profile) and have her look out of the corner of her eyes at the camera. And finally, the grass coming up over her wrist gives the appearance that her hand is either cut off or buried in the ground.
Shot 2) The lighting here is a bit flat (particularly in contrast to the other three shots), and the image seems a bit underexposed. Great depth of field here - she is nicely sharp yet well separated from both background and foreground. The solitary branch in the foreground is distracting, however. This is a great angle to shoot a "nature glamour" shot - it's the only one in the group that shows off her curves.
Shot 3) Nice shot - I like that you've zoomed out enough to put her in context. Another tricky lighting situation, but you've been able to keep enough detail in the shadows and not blow out too much of the highlights. The large sunburst is a bit distracting...you might want to take a step to your left next time so that the sun is peaking out from behind the tree rather than being unblocked beside it. Or you could shoot this in landscape orientation which would let you keep the forest context but remove the bright spot.
I would suggest moving her off the centerline in your composition (for example, if you were to shoot this horizontally I would add to the right side of the image rather than equally to both sides). There are also some things about her pose which are not classically feminine (there are better posts on here to explain that), things such as having her body almost square to the camera, or having the back of her hand square to the camera. I do like the way her leg crosses in front of the other and the tilt to her shoulders - this pose is far from a bad one in my opinion, but it could be improved. You could have her really accentuate the angles in this pose (kick her hip out a touch more, drop her rear shoulder a bit more, etc). You could also turn her so that she was either in profile or 3/4 profile, leaning so that her upper back/shoulder blades were leaning against the tree (rather than what seems to be her outer shoulder or upper arm)...these poses would do a better job of accenting her curves. Not that I'm an expert, but here is a relevant shot of mine to illustrate:
Shot 4) I like that you were able to get a different expression out of her (and I like that it was enough of a priority for you to try for it). This one looks a little over processed, especially compared with the other three, and I think a tighter crop would help here too.
Again, nice set. Please take these as constructive suggestions.