Dodge/Burn with Curves

You can use a Curves adjustment layer to brighten (dodge) or darken (burn) selective areas of an image.

For example, in the image below, I added one Dodge layer to brighten select areas. The result is an image that looks more dynamic and less flat:

In your adjustments palette, choose the Curves icon. Drag from the middle up for brightening, or down for darkening:

This automatically makes a mask for you. Invert the mask (command i) and then paint with a WHITE SOFT BRUSH on the mask, just on the areas where you want to see the change.

Remember, on a mask: White reveals, Black conceals. Above, I have painted with white JUST where I want the change to show through.