I do alot of architectural photography and I usually have just 2 strobes on location. So sometimes I need to add a spotlight in the room so I use this technique for doing that.
Before I used this technique I would dodge the area but that was messy and damaged the pixels color integrity. So now, if you use this method you can get the results you are looking for without any distortion. sample1.jpg sample2.jpg sample3.JPG sample4.JPG
You can also change the color of the object to yellow/blue for a warmer or cooler look. This technique also works great in any photo where you need to add light, especially on landscapes like the ones shown below.
You can also adjust layer opacity for more subtle light, and just copy the layer to add more spotlights if you wish. I use this everyday with photos that I need to retouch, hope this helps! http://www.williamtorrillo.com