[REQUEST] Help getting started designing profiles

[Corroded]

Hello

I have alot of experience using Photoshop, but mostly, I'm just using it for my own sake. Making wallpapers, experimenting around etc.
But now, I'm interested in starting to design some actual profiles both for me and possibly for others, should they be interested.

The design on my profile now is very basic. Just a header and a Carbon Fiber pattern background that I made for the sake of practice.

Bottom line, I've got the basics, but I'd really appreciate some guidelines / tips / tricks to be able to make some more advanced / better looking profiles.

And just a couple of extra questions, what size is the BG image? As of now, I've just made a pattern that repeats itself over the whole profile. How would I get a good resolution background, and make it so it wouldn't repeat itself?

Thanks in advance, any help will be much appreciated!