I'm not the best to answer this, guys like @Mr.Baller and @boubabi would be the best to answer, but I'll try.
You really need to focus on your composition for a clean sig. Think about render placement and text placement, and don't be afraid of changing stuff around if it's not working.
Lighting is also very important, you want it to be clean, but not just flat. Baller's recent sig here is a good example of it:
The background is fairly simple, but has some depth to it.
Try different things with stock work, keeping things interesting but subtle.