How to do galaxy nail art
Start with filing your nails in one direction.
Apply a base coat nail polish to protect your nails.
After that, apply a base color. The color I used is a shimmering black one.
For the next few steps, you're going to apply some colors with sponges. You could basically use any sponge. I used these, they're quite rough.
For my nails I used several colors: green, pink, purple and blue. You could also use only green and purple. Put some of the nail polish on the sponge and carefully pat it on your nails.
Add a see-through nail polish with glitters.
Et voilà: your galaxy nails!