Okies here are my all CnC.

You are doing great with everything but the render. Your bg and effects look nice in most of these but the render is either not part of the sig (mario, guy in suit) or is over blended (banana hair, lady with helmet). Work on playing with the colors of your render so they match the sig better and try to avoid ever covering them completely with any other layer. Also don't forget how much strong lightnig can help in bringing everything together, most of these have the same lighting throughout. =D

Good job yaky