Most important is to use a dark nail polish as your base coat, like black or dark blue. OPI Black Onyx is a great choice. Then add other colors with a small sponge. By adding a glitter coat on top, you get some stars. I would use something similar to Stairway to Heaven by Deborah Lippman.
Haven't tried yet, but i definitely will. So say we all!
Here is a small tutorial