I've got to be careful when i comment this, because last time i got neg repped for helping.
you need to get away from using those kind of backgrounds. They don't look good. You need to start using brushes, make you're own funky backgrounds.
If you're going to use something like that, then you need to hide it behind brushes and make lighting and colours effective.
Its too small for me to go into more detail.
Can i suggest something? Without getting neg repped. Follow tutorials for a good 6 months from now on in. Find out all the techniques from tutorials then let rip with your own imaginative sigs/avatars and wallpapers.