I think, over-all, the image has a nice look. The head seems well attached, but is is hard to notice it with the brighter body. A brighter background behind the head would make the head stand out better. The blurred background works well, but you got sloppy around the edges. Blend the blur using the clone tool set to near 30%. I have done this very carefully in images such as this:http://www.cosplay.com/photo/2326342/
Your white cape is blown too bright. You can bring it down using the burn tool, or go to Image, Adjust, Shadow/Highlight.