Hi,
Biggest issue is I couldn't notice your collar at all and the lack of texture.
If you're just trying to show off the hair and collar then start ditching some of the other unnecessary things. Here I just dropped the face entirely.
Made the hat all fancy and crooked so people know she's a
witch wizard lady.
Your colour count was actually fine (although i did reduce it a smidgen), but mostly you didn't have good value ramps (and I threw in some hue shift, but ignore that for now).
Hope it helps.