bit simple, the halo renders quality is bad...
the C4Ds dont blend (maybe lower the opacity or set it overlay etc, etc)
background needs some more work (try adding a texture or somthing)
otherwise its not bad for a 1st..5/10
Better than my first, but don't try to jumble everything in there at once, (C4D, RENDERS EFFECTS ETC). Try and master the simple techniques then start to add more advanced aspects into your sig.