Original picture:
[img width= height= alt=]http://www.elfquestfanart.com/MGalleryItem.php?id=981[/img]
Drawover:
[img width=347 height=444 alt=]http://www.elfquestfanart.com/MGalleryItem.php?id=983[/img]
1) The neck: In this position, her neck would have a curve like I've drawn in. Also...touch the base of your throat...notice how the neck ends right where your collar bones start? I can see that you know the neck has an inward curve at the front, but I don't think you made the connection that it is at the same location as the collar bones

2) Gave her breasts a little more roundness along the underside, so they are more gravity-appropriate.
3) This is somewhat subjective, but I gathered from the position of her shoulders that she's locking her shoulders and arms back and letting her chest push forward. A sort of reverse-slump. So, given that, I gave her back/waist more of a curve, to emphasis her posture. If were a human woman I wouldn't be so drastic, but she's an elf, so she gets to have a tiny waist. ^_^
4) Added a nostril mark. Little details like this can make a big difference, though strictly speaking, it isn't necessary. The style of your drawing is pretty minimalistic, so it works without it
5) This is a personal preference change. Bringing in her skull like I've done enhances the impression that she is looking up (as the neck changes did). Of course, if she had really poofy hair, your version would work too. So this one is, as I said, personal preference.
Lemme know if any of this doesn't make sense
