As I slowly work my way through Photoshop and how to use layers, I've discovered using textures as a way to give additional definition to my images. I'm sure there are better methods than mine, but so far simple works. I open the image I want to use and then open the texture I've chosen. I drag the texture onto the image and reduce the opacity. Then I use the eraser tool to lighten the areas where the texture seems too heavy.
This self-portrait made it to Explore on flickr.