For the glass parts, printing stickers yourself or ordering decals online would probably be neater if you haven't done it before.

For the metal panels, just make sure your preperation is thorough. I've done a bit of case painting. You'll need to make sure that the surface is very clean. You can give it a light sanding with some fine sandpaper afterwards. Then do a few thin coats of primer. Then several thin coats of your chosen colour, just quick & light, smooth passes with a spray can for each coat. After you have the colour coverage that you're happy with, apply a few more coats with a clear coat/lacquer to give it some resistance to scratches and so on. It's best to leave the last clear coat to cure for several days if you have the patience. I use Montana Black spray paint on my cases and it generally holds up quite well after clear coat is applied.