Okay there is a lot to CnC,
The signature is too plain---everything is the same,the colors,it doesn't blend.
The lighting---is only a little,like I can only tell the only lighting you put there is above the render,the render's pixels is broken because you used too much Burn Tool on him,I appreciate the blurred things but it still doesn't cope the random throws of yellowish fractals,you didn't use C4Ds too. The depth and flow is missing,everything about it is a mess. The text,I barely see it and I had to look again to see where your text is,the text placement is way off,the color doesn't fit anything and it is so small we need to dig to see it,the only thing that is perfect is that little nursey hat's color but that's it. Try more tutorials and you'll soon improve.
