Simply paint your nail white
Tearing a cosmetic sponge in half, paint blue, pink, and yellow stripes across the sponge.
And gently press the sponge across your nail. You may need to do this 2-3 times.
Warning!! It will get on your skin, but you can clean it off with a q tip dipped into acetone or polish remover.
Now I used white glitter. It's by KleanColor the name is I do; Romeo. It's a matte white glitter. Or you can use a toothpick and dip it into white polish and add white dots throughout the nail.