Easy Soft Focus Effect:
This effect works fine with lights & skins. It will add a nice glow to lightened objects, and a soft look for skin. Here we go...
I've picked this photo of Muhammad Ail Mosques from inside. It has a very nice lamps, yet I still can make them look much better ;)
Step 1: Duplicate the background layer, by hitting Ctrl+J to have two layers in the layers palate.
Step 2: With "Layer 1" selected in the Layers palette, change the blend mode to Overlay.
Step 3: With "Layer 1" still selected, go to [Filter > Blur > Gaussian Blur]. Well, the "Radius" value depends on the image you're using. So, keep dragging the slider til you get a satisfying effect. Since I'm using a high resolution image, I needed a high value.
Step 4: Lower the opacity of "Layer 1" (Optional).
Step 5: Change the blend mode to "Soft Light" (Optional).