hey guys i'm having trouble blending my render into my backgound.

i don't really know what tool to use...i've been using the smudge tool but it looks like crap when i just kind of want the shoulders and stuff blended in to the background.

any suggestions? thanks~!

Take a 10-20px soft brush set it on 75% opacity and slightly erase around the out side of him. Not too much though.