Has any1 got any good tuts for makin backgrounds?(for gimp)
But colors down then mix 'em together!
Really though it depends on the render. As long as the render blends well with the background... you'll be fine

Hm...... copy the render a bunch of times so it fills the canvas. Filters>noise>pick @ 100 for both options.
then Filters>Map>Van Gogh keep all default.
Pretty decent beginner's background that looks nice and "soft"
Brushes-Stocks-C4ds-Multiple render-smudge, etc....