Another edit:

One of the biggest problems with this (and many other's RPG sprites) has to do with perspective. Generally speaking, rpg sprites are mean to be viewed from over head, and here it seems as though we're looking at the character face-on. So, basically I reworked the image with that in mind, and tried not to change your design too much. (oh, I changed the pose in general, a bit, as well, as I thought it looked a bit stiff).
The other changes were a lot less drastic. I reduced the colour count by unifying the palette a bit, and added thing like a bit of shading to the face, and highlights to the hair. Also upped the contrast quite a bit (especially in the hair), as the original colours were basically indistinguishable from one another, even at, like, 10x zoom.
I'd also suggest taking a look at some tutorials, and maybe studying some old games as references.