Well you can't make every sig after a tutorial. ^^ Eventually you'll need to stop referring to tuts and use what you've learned in tuts on your own. The only reason you should use tuts is to see new ways of making sigs. Once you've learned those new ways, do not go back to the same tut. Use those new ideas you've learned and execute them on your own.
Anyway, like EJ said the lighting looks fake. Realistic lighting is what makes sigs look sexy. Also your C4D is behind the render and it's blurred. Yet the background sharper than the C4D in front of it... Whenever you blur and sharpen make sure you're doing it for the right reasons. Usually sharpen your focal or anything "closer" and blur the bg, or anything "further". This is just a general way of creating depth and is not always done like this.