@ Lawrence Will do so.
@Kapptin It should be snow in the hair, but it seems it didn't worked oute, eh? =/ Anyway, I understood what you meant when you said about the shape, but I'm really clueless what to do.Could you give me a clue, if that's not much trouble?

I actually really like that super-bright highlight. It's totally realistic if the coat is shiny plastic or something. Unfortunately the rest of the image is not smooth and not very well defined. You need to do a lot more to bring out the shape of the character in general. Also, you don't have space to dither on the hair, and those colours are way too far apart to dither (in most cases I guess) anyway. Add a colour or find a way to make it work with just those, but that way is not the dither.

Is that yellow line down the back supposed to be a highlight from the sunshine? If so, then I'd say it's too bright. Try to get a colour halfway between the bright yellow and the blue of the jacket.