http://img231.imageshack.us/img231/6898/inc0zj.gif
http://img464.imageshack.us/img464/4590/dante25gy.gif
http://img153.imageshack.us/img153/8430/cap1tn.gif
http://img473.imageshack.us/img473/2378/bakuryu2mu.gif
C&C please
Printable View
C&C please
The first one:
To me it looks a bit bland and boring, nothing really jumps out at me. Try adding some parts of more interest.
Second:
I actually like this one. I beleive the render jumps out as the main focus of the signature. The only thing you should consider there is maybe some lighter colours.
Third:
I don't particularly like this one, it's a bit too bland for my taste.
Fourth:
Your text needs work, keep trying to perfect it. Also, the render doesn't match the background of your signature.
Overall:
Keep working at it, you will improve!