Neat piece, but I'm really not caring for the palettes on this one. I don't really find the orangy-red, yellow and purple to be an aesthetically pleasing combination, and more importantly, the focus of the piece seems to be sorely lacking in contrast.

Your skin tones only vary by lightness, the hue and saturation stay pretty consistent, which leaves his face feeling kind of flat and uninteresting. I'd suggest playing with your palettes a bit and being a bit more experimental. Similar issue with the hair. I'm also bothered by the fact that the darkest shade for the hair and skin blend right into each other because the only difference between the two is the hue. If you convert your image to greyscale it's almost impossible to tell where the hair ends and the face begins.

Don't be afraid to really push the contrast in your pieces. This has a lot of potential, the face is very expressive - don't loose that in flat colouring.