A quite simple and interesting Photoshop tutorial for today, that has helped me save a lot of images. In many ways, it's like dodging and burning, but with a lot more control. The twist here, is that it allows you to use colored dodging and burning, if you wish to do so!
This is what the procedure does:
1. Open your image. If it's not flattened yet, flatten it. On the layer palette, create a new group (press the icon on the bottom of the palette). Select as blending mode "Vivid Light".
2. Create a new Layer, and set its opacity to 50%
3. Pick a round brush and set its hardness to 0% and its opacity to 20-40% (tweak to your taste). You can also add airbrush properties, with a flow of your desire (I use 30-40%). Then you can "paint" the image, keeping in mind that the dark shades work as burn, the light shades work as dodge. So, white would be the maximum dodge and black the maximum burn.
4. The fun begins when you realize that using actual color reflects on the image! So, a dark red will not only give you a burn effect, but it will add a reddish tint (directly proportional with the saturation of the color you picked; high saturation = lots of reddish tint).
Simple, fast, and very effective, although of course it will require some practice to know how to use it to its fullest