A really in-depth tutorial on how to create a nice abstract art style wallpaper.

Inspired from Summer Collection - Wallpaper by Benjigarner

Begin by representing the file that would have 1600x1200 px and 72 dpi. 

Choose after that the Rectangle Tool (U) to draw the background of the picture to be.



Select next parameters for the made layer by making a mouse click on this layer on the layers’ palette.
Blending Options>Gradient Overlay



Gradient’s parameters:

 



Use the last applied tool to draw this time a vertical stripe.



The layer’s parameters: Fill 0%
Blending Options>Gradient Overlay



Gradient’s parameters:



Blending Options>Stroke