Well seeing as its your first its not that bad. You've got a good render, and you've tried to use a C4D which is good. You've also tried to blend the render which is good. Now the problems are that the text isnt very well blended. Basically it takes away from the focal point which you want to be the render. You can change the style and opacity and colour to make it blend more. The C4D isnt very well blended either, basically your going to want to erase parts of it and change the opacity and blending options. With the render id start off basic, just try and doing some smudging on it and see how it goes, it could work quite well. Also id try and keep the colours within one shade group e.g. blues + purple and light blues etc. would go well. Dont have too much of a contrast in colours.
The best advice i can give atm is to watch some tutorials see how they do it and then try and apply that to other sigs. Your have the potential to be good