Here’s another great video from Phlearn that shows you how to use the lens flare filter in Photoshop. As you’ll see, the key is to using an appropriate backlit image and making sure that you align your flare source with the actual light source. But check out the video for some crucial tips on making the lens flare more natural.
The Best Way to Use Lens Flares in Photoshop
[youtube https://www.youtube.com/watch?v=Tl09WHy_neg&w=700]