need suggestions for improvement

Ontario said:
Try not to center your focals. It is hard to make a signature look good with a centered focal (don't get me wrong, it's been done before), but for your sake I would stick to one of the sides. Once your improved and feel you can pull it off, I say go for it (Here is a link to the "Rule of Thirds" page that should help you out a bit: http://en.wikipedia.org/wiki/Rule_of_thirds).

Also, try blending your render (if that is a render) into the background. Don't just stick the render on there, give it some flare. Use the burn/dodge tool or whatever to make it look like its sort of blended with the BG and not just plopped on there.

I would stay away from using text. I find that unless you can do it really well, adding text just makes the piece look worse.

Try to match the colours of your render with the BG. You can use sites like http://kuler.adobe.com/ to find out what colours go good with other colours. There are several methods you can use to colour something, but I don't think you should worry about that just yet, just the basics down.

Sorry if I seemed a bit too picky, only wanted to help. You can have my msn if you want me to clear anything up.

The sig isn't that bad. If its one of your fist, don't feel discouraged. I was even worse when I started out.