Dodging and burning are techniques that have been around since the beginning of photography. If you're unfamiliar with the terms, dodging simply means to "lighten" portions of your photo selectively and "burning" means to darken areas during the developing process. 

In software, we can do this with brushes and brightness settings. I'm a little picky (as if you didn't already know that) about my images and I want total control over where I darken and lighten so I don't typically rely on overall "global" adjustments. I prefer to get in there and dodge or burn small areas, incrementally, to build up an effect to my liking. The way I do this is to create a "dodge and burn 50% opacity" layer. Don't's much simpler than it sounds.

Here I have a photo straight out of the camera. The only thing I've applied is a lens correction and chromatic aberration adjustment. It was taken in early morning light at Magnolia Plantation and Gardens in Charleston SC.

It's a nice image but with the Spanish moss being lit from the sun and the flowers near the water in shade, it presents a visual roadblock for me because the eye is not going where I want it to go. Typically, the eye goes to the brightest area of your photo. Here, that's along the edges which takes the eye out of the photograph. 

In order to help guide the eye where I want it to go, I create a dodge and burn layer. This does not use the "dodge and burn" tool in Photoshop. Instead, I create a blank layer. I then fill that layer with 50% gray by going to "Edit-Fill-50% Gray"

After that, the whole image turns gray. I then go to the layers panel and change the blending mode from "Normal" to "Overlay" and my image looks normal again. 

I select a soft edge brush, set the brush opacity to about 10 to 15%, and I use a white brush to paint areas that I wish to brighten, and a black brush to paint areas that I wish to darken. The effect is cumulative, which is why I choose a low opacity brush. 

After about 30 seconds of brushing, my image has taken on an slightly different look. I have not made any saturation, overall brightness, or contrast adjustments. Further processing might be necessary but this is a good start.

Looking at the images side by side, you can see the difference. The eye gravitates more toward the bright white flowers than the top edge of the photo. This effect can be subtle or more dramatic but it gives me the control I want to help the viewer see what I intended them to see when I took the photo. 

If this is at all confusing, I have a YouTube video on this process as well as a video that shows how to make an "action" that will create the dodge and burn layer, fill it with gray, and change the blending mode all in one click. It truly is a wonderful tool to have in your creative processing collection.