This technique offers me the ability to add texture to inherently textured elements of some of my images. It all depends on your Photoshop skills but you can apply this technique as you feel best suits your image and ability.
I have summerised each process and assume you are familiar with Photoshop techniques.
Start with an apropriate portrait of a textured face, or a textured object.
1. Duplicate Layer (Ctrl+J)
2. High Pass on this layer (Filter - Other - High Pass set around 10 to start)
3. Overlay - Blending mode ( Layers Dropdown)
4. Duplicate Background Layer and place it on top of other layers (Ctrl+J)
5. Desaturate this layer (Shift+Ctrl+U) set blending mode to "Soft Light" or "Hard Light" depending on preferences.
6. Flatten all layers
7. Duplicate new background Layer (Ctrl+J)
8. High Pass on the new layer (Filter - Other - High Pass set around 10 to start).
9. Set blending mode to "Overlay"
As indicated each layers effect on the overall look and feel of your image can be adjusted by changing the layers opacity (Fill). The end result can be as textured as you like.
By selecting and masking layers you can select areas of an image to apply this treatment to. Here is an example of an image I used