Really solid body and costume. Most of the issues are with the head I think. That said I did make some minor alterations to the body so take a look at those side by side, most importantly the lower legs being different sizes.
As for the head right now you're going completely round. The face is longer, the cranium is round but don't forget about the jaw, give him a chin. As for the eye give him an upper eyelid and an expression, right now it's just completely wide open. Eyes are important to personality. Don't forget the eyebrow. The hair is kind of just a mess, try to give it a bit of flow in specific directions.
You're using a lot of colours that don't really do anything. Scale it back to your base colours for now until you start shading. Don't work on this bright blue. Unless you know specifically what background you'll be displaying on use a neutral colour like a mid grey. Using a bright colour will throw off your perception. Plus it is unpleasant to stare at while working.
As I said very nice work on the body. Maybe take a closer look at some anime references and see how they shape the head if that's what you're going for.