I like 1 for the fact that the colour of her hair sooo goes with the colour of the leaves in the late afternoon light, and you saw that and worked it out.
2 is nice, too, and you applied the fill flash wisely.
The last has her giving you a cheeky smile, but - like has been said - the pov is not the most flattering to anyone.
I appreciate the advice. One thing I've learned now is not to shoot the upward angle from now on. LaFoto, you are correct about the first photo, I really liked how her hair blended in with the background. Also this was more of a candid shot anyway, since I didn't tell her to stand with her back towards me. I guess I should have explained myself. Thanks for the comments!