This is a VERY simple way of creating a "painting with light" effect, by using dodge and burn layers
1/ Open your image in photoshop (make sure your not working on the original)
2/ Add a new layer on top of it and fill it with black (bucket fill). Name it Highlights and set its blending mode to "Colour Dodge".
3/ Create a second new layer, and fill this one with white. Name this one "Shadows", and set blending mode to "Colour Burn"

Now your ready to start painting with light.

First of all, with your shadows layer selected, use a black soft edge brush, set at 2-5% opacity, and paint in areas you want richer colours and darker shadows.

Then with your Highlights layer selected, use a white soft edge brush set at 2-5% opacity, and paint in areas where you wish to see brighter areas and colours.

Remember, any action can be undone by simply painting white on white, or black on black (same as layer mask)

Finally adjust saturation/vibrancy to your taste

What you end up with is something along the lines of the image below (before and after

Tutorial and images © Chris Hodgson