Your smudging is really messy and doesn't really make a good background for the piece. Have you considered taking some C4D renders and using them to help shape your background? As I see it all of the smudging and the effect C4Ds on screen give all your tags the same look and a messy feel. It gives a really LQ look when you do that, and causes them to lose depth and just generally not look good.
Some tips, lay off the sharpen - it is good when finishing things up and creating depth but sharpening the entire sig or oversharpening the render makes everything look flat.
Work on effects. Use C4D renders to build depth and to help develop lighting.
Stop smudging so much. Yeah, they're some cool smudge tags but smudge tags are what everyone first learns.
Work on your composition and remember that the rule of thirds is your friend.