I'd say maybe go with a more 'streamlined' look for Quicksilver's hair. I know it sounds strange to say streamlined when his hair is that shape, but I mean maybe go with a look that shows the strands of hair instead that follow the shape of the hair. Or, if not that then maybe use a slightly lighter gray for the basecoat? At the moment it's giving me the impression that he's got snow on his head since the white seems to contrast the gray too much.
But still, nice job for a first attempt. That paintjob on Moleman suits him alot! :)