[*]1. Your renders are distorted
[*]2. The renders look like they were slapped on there.
[*]3. Background is just a bunch of brushes.
[*]4. Text is terrible, doesn't match the flow of the signature. (If there is any)
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Look at something I made:
[*]1. Render isn't distorted.
[*]2. Render is blended in, DOESN'T look slapped on.
[*]3. Background has smudging, effects, etc.
[*]4. Text matches the flow of the signature.
[*]5. C4D was placed in a nice position, looks good.
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tl;dr: A blind monkey with it's eyes stabbed out could do better.
Try reading up on some tutorials, on youtube and some graphics websites.
NOTE: Not trying to be mean, just giving some CnC.