This is the very first time i used a c4d, so tell me the goods and bads of it. (btw, im a begininer with gimp...) v2:
I completely agree with mace. Both the C4D and the render have been over-smudged. The colors don't go well either.
The idea of C4D is not to use the C4D as a standalone background, but instead to provide small details to your final work. Read up on some tutorials, I believe there's a link to some official ones in the resources topic found in this forum.
In this case, definitely. The lighting is also pretty bad on the leg. Plus, the text needs a little texture. Try throwing a clipping mask on it with some subtle effects over it. I have a tutorial here if you need it.
It might help to play around with the burn tool on the leg so that the color matches the rest of the character better. Putting a little color over it might help too.