So anyway...first. One huge thing I noticed is that the eye seems a little...up there. They should be down a little more.
The colours are very nicely blended, and the shading is mostly in the right areas.
Though the bright streak near the forehead looks awkward. My only guess on that was the layers may have jacked up a little, cause' it happens sometimes, therefore not fully your fault. Otherwise, a little fixing would do well.
If it is supposed to be a glow for that diamond shaped thing, maybe different sort of fading colour shades would do well there.
And again, the stray colours don't stand out a lot but be super careful not to go outside the lines! :3
That was all I had to say on the matter. Other than those things, this is a really nice picture. Good job, and watch the little mistakes! : D