Better if you not post links next time. They still need a lot of work. Some of the signatures are too empty and they look quite boring.
Another thing is text. No offence but one or two of them looks quite weird imo. They don't fit in with the entire signature and they look too big. You should blend your renders in with the background. Plus, don't desaturate your render on some of them, like others have said on other CnCs.
You should look at some tutorials to help you. Keep them coming and keep trying!

Peace,
Chucks