First you want to select you color swatches. This is the most important part of the tutorial. Color selection is everything. I picked the colors of green to yellow from. I got these from the swatch PANTONE Process uncoated. To see all the color swatches check this out.

 

Create yellow-green to green-yellow gradient for the background. I used colors #cadb36 to #96bc32.

 

 

Take some vector brushes. I recommend Magurno brushes. Use a sorted amount of dark yellow and dark green brushes. Try not to let the brush fade against the background gradient.

 

 

 

Duplicate the vector brush layer. Lock one of the duplicates.

Select the eraser tool and grunge the vector. I recommend my grunge brushes and greycobra's brushes.

 

Final Result:

 

Dr. Photoshop Wallpaper Example

 

Discuss the Adobe Photoshop tutorials on the forums. You can find the photoshop files to download there too.