High Pass Sharpening

1. On the Layer palette select your Background Layer and right click. Select Duplicate Layer.
   
2. With this new layer highlighted select Filter / Other / High Pass. Set the Radius to 10 and click OK.
   
3. Zoom into your image to Actual Pixels level so you can better see what you're going to do next.
   
4. Go back to the Layer Palette and select Soft or Hard  Light from the left drop down.
   
5. Now go to the Opacity Slider and select a level of sharpening that seems best to you. Usually something between 20% and 70% will be best.

That's all there is to it..
Below is the end results of this procedure.

Filter / Other / High Pass  ---- Radius set to 10

Final Image that has been sharpened --
Opacity slider set to 20-70%