You need to blend in your renders into the background. This is done by using the smudge tool. Experiment with different settings. You'll be surprised what you can make with different settings.
To smudge, after you apply and experiment with different settings, you brush around the render. Add a new layer, and then smudge it again; you can erase whatever you want.
Here are a few ideas:
1. Use Gradient maps - Your colors don't fit well with your render.
2. Use the liquify feature, and lower the opacity. Again, erase parts what you don't like.
Secondly, try to use only 1 render. Using more than 1 screws up the focal point, unless you're really good at it - expert.
Thirdly, a good size for a signature is 300 x 120.
Fourth - last, but not least, use different text. Try downloading this one called Liberation Serif, use Ariel, Georgia, or something like Franklin gothic. Also, don't make your text so big. You are making a signature, not a banner. Text in signatures should be small, and should not be something like "look at me, i'm the center of attention!"