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Any pointers that I should keep in mind would be awesome!
I like the pensive mood in #1. This is probably beyond your control, but you might want to be aware. Because of your angle and its color, the bra strap on her shoulder gets a lot of attention. That may or may not be important to the subject.
On #3, the combination of angle and focal length tends to make her legs look disproportionate to the rest of her body. What focal length lens did you use? Was it your intent to emphasize her legs? If you consciously chose the angle and focal length to emphasize her legs, then that's a decision you made as a photographer. However, if it was unintended, you need to understand how these things interact to produce the outcome.
As a learning experiment, I suggest you go back and reshoot #3 using her posed just like that and from the same angle. Keep her the same size in the frame as you have now, but take a succession of images from the most wide angle lens you own to the most telephoto lens you own, with some intermediate focal lengths between. Ideally make 8x10 prints, but at least compare on a fairly big monitor. Notice the difference focal length makes.