1. It looks like the camera focused on her hair, not her eyes. Choose the focal point that corresponds with her eyes. You might want to selectively sharpen the eyes just to see if you can get some more clarity in them.
2. I love her expression, but the background bugs me a little. The stick thingy (sorry I can't think of what it's called) hanging down in the window bugs me. Also, it looks like the flowers are growing out of her shoulders.
3. Very nice. I think I might try a tighter crop on her face. I don't know if you used fill flash, but it would have been nice to get some catch-lights in her eyes.
4. My favorite. Beautiful expression,composition, etc. The only thing that slightly bugs me is that you cut a little of her head off, but it doesn't bother me that much.
5. Again, beautiful expression. She has gorgeous eyes, btw. The background might be a tad busy.
These pictures are very nice. Keep up the good work!