Hmmm I do not do digital art, and i'm not an expert at any kind of art >.<
Buuut (it's not with the clothes xD) I find the orange of his "plane-staff" (Don't know how to call it jajajajaja but you get the idea xD) too bright.
I have an idea, I don't really know if it will work, and if it's too dificult you shouldn't try it cuz I'm just guessing xD
Why don't you try inverting the shadowing?
I found this image searching a bit on the internet, and it show what i'm talking about (if you notice, there are more dark-areas thank bright-areas). I don't know, maybe it works .-. (Again, if it's too much work... you should wait for someone else advice xD)
It's the only I can do u.u
PS: I love that cartoon! (it's half cartoon half anime I guess >.< )