overall looks good. got alot potential maybe find a colour that suite the render like just make the bg darker. easy way to blend is use a nig soft brush and plot points on the edge of therender. you can also use a circle marquee tool and feather. and also too much head room on the render, aslo make therender bigger. text very nice.
I think the first thing to blend is the colors. The background colors need to kind of blend well with the render, so that it feels like it's one image. As it is, the colors are obviously different, and it sticks out a lot more. You could also erase a little bit of the render with a soft brush at 22%. Only do this at the base of the image, so that it doesn't look odd.
