its just that ur sig is really simple and i can easily tell what u did to make it, sigs shouldnt be THAT simple

u rendered blakc and white clouds, added a tiger render, duplicated it and flipped horizontally, then u added a text layer and used default stroke(3 px red)

www.pixel2life.com for tutorials, it will improve u by ALOT, trust me
and try to get some brushes
www.deviantart.com is a good place to start