Arigatooo~ I really like this piece even if it was just to test some random things.
im sorry, i dont get this kind of shading at all, im afraid. the shading is kinda all over the place, there's nothing consequent about it, and it doesnt pay any real attention to the light source... o.O
If you don't get it I'll explain you, unless you actually misread my comments on DA I said it was to test a new HAIR SHADING technique, the rest was done in a good hour just cause I felt like finishing it and cause I had nothing to do (and it still respects the lightsource).
As you can see I'm doing cell shading which is probably the easiest way to color when you don't have a tablet -I use a laptop PAD, yes I'm probably the only one mad enough to work with that but I can use it better than any mouse-.
When it comes to hair, cell shade is whether about doing quick several big locks or lots of tiny ones with different colors to show some depth, or the gay -my way of calling it- technique with the "I'll put another color on the half back part and add 3 brighlights in front to show my pro fans where the lightsource is!".
Now if you look again at my cover you'll notice that it's neither of the two previous technique I've mentionned, it's kinda mix of cell/soft/random and if you don't see the depth and lightsource then I can't tell you what's your problem cause it seems pretty obvious to me, if there was no depth the whole haircut of our beloved Deidara would be of the same color with the same locks pattern, is it that way? Don't think so.
(if this sounds really arrogant don't think it's against you, I've always been that way.)