Take a look at his posture, is he a knight or a rag doll?
sometimes, the background can really throw off the edges of art. This just really boils down to effective anti-aliasing and some positive color choices. Base the outlines around the color that he will be round in more than the ones that he won't be.
From a closer inspection, I noticed you have a wild choice of colors... You have random spots of a bluish color and your lightest shade is a strange green color.