Marty from Blue Lightning TV does a great of showing us how to create more natural lens flare effects in Photoshop. This isn’t an easy thing to get right. Sometimes it is obvious to see when lens flare has been added in post. The flare tends to look too strong, or the colouring is not consistent with the sunset/sunrise colours.
Marty not only takes us through a step-by-step tutorial on creating a nice lens flare effect, he also shows us how to naturally alter the colouring of the flare so that it is more congruent with the rest of the colouring in the scene.
But I would say, use this function cautiously. While added lens flare can sometimes add some depth to the scene, it can also take away from the composition in scenes where it isn’t needed. Subtle is key with the lens flare filter.