Painting a case is probably no different than painting an Asus Sabertooth's "Thermal Armor" or adding red accents on some black RAM sticks. Granted you have to approach them in different ways, but the same materials are used.
When painting a case you will probably need duct tape to cover the areas that you don't want to be affected by whatever you use to use (I recommend plastidip or spraypaint) and proceed from there.
You can find many videos on YouTube showing the painting of computer cases and components using various materials. I recommend not trying anything too "hard" to where you end up ruining your case's aesthetic appeal because you messed something up.
Good luck!