1. the background is a little busy, and it seems just a tad over-saturated (on my monitor). The flower is kind of icky, it takes my attention away from the pretty dragonfly. The one petal on the left could be cropped out, also. Or maybe you could just crop the whole thing, for more of a focus on the bug?
2. The same issues as with the first one, mostly. The dragonfly is more noticeable here, it seems, but the angle of its body isnt as pleasing.
3. I think you should crop this one a little, too. The light corner where the sunshine is makes the rest of it look dark, even though I dont think it's technically underexposed. An illusion.
4. This one would be better if the background was not in focus, though I understand it can be difficult with cameras such as ours.

I tried photoshop, and I was fairly unsuccessful.... So I mostly avoid this type of shot.
Her head is right at the top of the frame, too.