+ lighting is good
+ text isn't bad
-no direction, and no motion
This isn't the best example. But here goes with an old sig.
Notice the direction and motion of the sig.
Even the text is going with the motion in that direction
Notice I put some blue lighting on the face to make it look more real. It is poorly done...but it is there. That is a good lighting technique to incorporate into your sigs. Changing the color of parts of the render that would come in contact with that lighting in real life.
This isn't the best example of lighting or blending, But you should at least incorporate colors from the render in to the background. I chose to use yellow from his hair and tried to put a little orange from his jacket. I should have put more blue, but I was not thinking.
I hope this at least helped a little.