hmm it doesnt look like you use brushes.
go to
http://www.deviantart.com, go to browse, then pick 'photoshop resources' and 'brushes' and download all the ones that look good. and start practicing with them.
now bakc to the sigs.. the background is too red, too plain, you should only use one render and it should be bigger. the text needs a LOT of work, you should go read some text tutorials. actually read every tutorial you can find :D