Don't take this the wrong way and I'm not sure if it was intentional, but I really wish you would have used more blocks on her. Of course if you were going for a desired look or was pressed for time then disregard...
If you have a basic, flat, 2D shape to start with, you basically want to make 4-8 layers that are identical, then chip away from you character like a sculptor would and add definition. If you need pointers I'm sure theres a bunch that could help. You choice in colors on the final version are good, but it doesn't really require a giant talent to make these sprites. It takes getting used to at first, but if you have a general idea of what you're after and have some experience with the editor, you can usually bang em out.