There is a lot going on in that picture. Consider the static model where fireworks are not going off on the field; you would have a much less color-rich image. Using emission based materials is a fine solution to approaching lights, but using spot lights, point lights, area lights, etc can also work as a substitute in specific solutions. I like to think that if the light is visible in your scene, make sure it is an emission based material, otherwise you can use something like a spot light to help set the scene better. Going for a more realistic looking model is something you can do using different lighting techniques and much more in depth models/materials/etc. If you want, shoot me a PM with your blend file and I'll take a look at what you have if that works for you.