That actually looks really good for a first sig, check out the "First Sigs" thread in this forum and you'll see how good it really is.
Anyway that's a tough question to answer because there are so many different things you can do in Photoshop. I do not consider myself an expert by any stretch of the imagination, I'm learning new things myself all the time. Basically what I would say is to keep messing around with Photoshop, try all the different effects and filters. Maybe Google search "sig making tutorials" or something for more detailed help, I know there are lots of tutorials on Youtube. Another thing is try making stuff without trying to keep it under Cafe limits, it'll allow you to try and do more. You'll learn what you can and can't do through trial and error. So really it's like anything you want to get good at, just keep at it.
If you have any direct questions about techniques I'll answer them if I can.
Oh and the sig you're wearing now is badass by the way.