I'll give you some more indepth stuff, you'll get nowhere with basic "Yeah it's ok" comments.
Backgrounds:
The thing with backgrounds is that they can save a graphic. You can make something seem great without having a spectacular main pic or good text... I've noticed with yours you're operating without brushes and stuff, but you basically have two options if you want to make good backgrounds:
- Brushes.
Download them from Deviantart.com, and read the mini-tutorials on how to install them. They're listed all around the place, the most basic way is to download them then copy/paste them into your Brushes folder, which is generally located in the Presets folder of the main Adobe Photoshop CS2 folder. Go to GameRenders.com and check out their tutorial section. Ignore the fact that nbalive744 goes there, because their BG tutorials are actually very good. Experiment a bit with those and learn some new things, then try it out with some sigs. Just create a 500x500 image and screw around with the brushes to get used to it.
Example:

- Pictures.
This is one I used a bit when I was starting out, if you can get a decent graphic I'd be more inclined to fade that into the background or set it to Overlay or something. Never underestimate the power of a picture background when you're a beginner, not enough people use it IMO and if you do it properly and use decent Adjustment Layers (Layer > New Adjustment Layers) it'll look pretty cool. What you're doing now is too plain, but you can easily change that so not to worry. Test it out first, like the brushes, don't rush in and make a sig with it straight up.
Example:

- Brush + Pic
This is probably my favourite, and the one I use the most. If you can combine both brushing + pictures it can make a pretty sweet background. It's a little more advanced, so one to try when you get more accustomed to doing things on PS but the main things you'll need to use are Adjustment Layers (Namely Levels, Curve and Colour Balance) and layer effects like Overlay, Darken, Soft Light etc... it takes alot of experimenting and sometimes it can be hard to get the result you want, but if you can master it it's definitely worth it.
Examples:



Text
I'm not too great with text, but the best advise I can give is to just keep it as simple as possible. Block text usually works better than script if you're just beginning, you'll see in alot of my stuff that I generally just use plain white Impact or Big Noodle Titling for my text. It might be basic but sometimes that's better.
With the positioning, try not to just have it floating around. Personally I prefer it to either be A) in between the end of the graphic and the border, or B) hugging the border. As far as I'm concerned, unless you do something fantastic with your text the focus should be on the picture and the background.
Pictures
Colin's the master at this, but you definitely should use Layer Effects. It's so amazingly simple, all you do basically is right click the layer in which your main picture is on, Duplicate it, and set the Duplicated layer to something like Overlay, Darken etc. It gives the picture an added quality, and personally I just think it looks alot better since most pictures you'll use aren't really well lit so nothing is accentuated. For instance, with a simple Overlay your 50 Cent pic goes from this:
To this:
It's a small change, but it's an improvement none the less.
Hopefully you can get something out of this, if you've got any questions just say. This isn't really advanced stuff but as a beginner it should be helpful. To reitterate though, definitely go to
GameRenders.com and check out their tutorials, it's very helpful.
As far as borders go, I create a new layer, Select All > Select > Modify > Border 1 or 2 px > Edit > Fill with whatever colour you want. You get this:
