Disclaimer: I'm no pro, or even close, but here's some C&C:
I think that the composition is nice in all four of them.
That said, here are some comments:
1. The color seems off (though you say you were going for that look--why?). Also, it appears that she was squinting--do you have another shot of this pose where she wasn't?
2. They look underexposed. Did you use fill flash? If so, a little more would have helped (or brighten their faces in post).
3. I disagree with the poster above, I don't know why you'd show off the ring in this shot (I'd do a different pose for the ring shot). I'd actually ask her to lower her hands like he did.
4. I really like this idea. However, the strong sunlight in the upper right detracts from this shot. Maybe a different angle would have helped. I'm not sure how this would look, but I might also try this shot with more shallow depth of field, so that only he or she would be in focus--right now you've got the background in focus as well. The color seems a bit off on this one as well.
They're really nice, though. It seems that you've got ideas and an eye for composition.