This is my first tutorial, in which I'll demonstrate how to create a BG that looks like this:
First, choose the colors you want to do then go to filter->render->clouds
Next, go to filter->pixelate->mosaic, and set the tile size to about 5
Finally, go to filter->stylize->glowing edges
For the settings, set the edge width to 12, the brightness to whatever, and the smoothness to 5 or 6
Here is the finished product
This is what you get with a lower and higher smoothness
