Xandi, I think you are doing very well indeed with the focus of your render (i.e. the character), but for me, I'd like to see a more meaningful background. I'm not sure how you are doing them at present, but I always use a 3D set (e.g. a modelled room or street scene) even if it can hardly be seen. This puts your character in a "real" place, and allows shadows, natural depth of field, etc., and importantly gives the edges of your character a smoother and more realistic look so that they look less "cut out". Essentially it allows the light to behave more naturally.