Good points-
Nice colour
Followed the rules perfectly
used off black colour and followed other tips from earlier.
You could improve by-
Again with the layers and lock alpha, all you do is click the colour layers and the lock alpha box then you can't go out the lines. just realized it could be my mistake and I cant tell if you did use lock alpha but i can see colour I didn't think was there
use the airbrush to get smoother colour on the belly