Hey Rob,
I really like the angle you chose (more interesting than the usual forward facing mirrored look), the shading and the proportions are pretty good. Althought I would agree with Malor on all of his points about saturation and contrast. The bright green hair isn't all bad if you were going for it.
One more thing you should watch for is how AA is done. The purpose of AA is usually to blend the outline into an adjacent color, so picking colors between the two are crucial. For instance in this work you need to go between the purple outline and the tan background.
Hope you didn't mind a minor edit on the left (our left) side of the face outline:
I've added two new colors but having a slightly larger palette at this point won't hurt too much. Also if you wanted you could work the colors into the background or shading perhaps.
Excellent start!