Banding, thick bands, draw attention to the borders between since something change there. It will make the eye think, hey, this area is important. But, often with banding, it's noticeable but serves no function other than confusing the eye. By compressing the bands, the change is over so quick the eye doesn't see the borders. And, you can place the banded edge near a place on the form where the light changes from light to dark naturally because of the form's form.
Super quick edit. I didn't really optimize the pixel placement here and I left some areas rather messy.
Notice the band compression here, on the red dress, particularly the "shelf".
Many minor pixel details were removed. You don't need to render fine details like teeth or nails. Some of the outlines can be simplified so the lines flow better, too. Outlines can have a little color to them if you feel that the black is too heavy. Large shapes like the hair don't need equal colors everywhere, it's okay to go darker and lighter for large areas.