How to Handle Flares
Consider the characteristics of flare in an image: lack of contrast and washed out colors, as well as warm hues. When processing pictures with strong instances of flare, we need to counter these characteristics to balance out the image and retain enough detail. For such images, increasing the contrast, deepening the blacks, and adjusting the hue should do the trick to make a good flare image look great.
If your image would benefit from additional flare added in post, make sure to provide enough light in camera and match the lighting direction to make the effect look believable.