Ok, so we talked about using c4ds, fractals or other stock images to add something to the empty spaces.
This is what i'm talking about.
All i did here was add a stock image of tree bark:
I blurred the edge of the focal slightly and i added a few gradient maps to help with depth, color and lighting.
So you're really good at getting the base of your signature. Now we just have to teach you how to add the finishes touches to it.
Try make a new signature similar to this, where you have kind of a hazy, empty background and then come up with some sort of stock of c4d to fill it out a bit more. =)