C4Ds add much effect when u use the properly ^^
U got the lighting, its good
Depth, is nice.
Now gonna list the bad parts.
Totoro looks over sharpened and thats a bad render.
U didnt blend him into te BG, dont forget blending, it is very important.
Try this tut: beginner signature tutorial | Photoshop Signature Tutorials - Sigtutorials.com
i like that u r progressing and that u r actually sticking to ppl's CnC, not like some novice who are full of themselves and say that they dont need any CnC or tuts for improving..
If u KIU like this u will be a good sig maker in some months