sorry for the bad photo :(
what you need :
1. black nail polish
2. blue / dark blue nail polish
3. pink nail polish
4. glitter nail polish
5. sponge
first, paint all your nails with black nail polish, wait for it to dry
then dab your sponge into blue nail polish and pat it on your half of your nail. I pat it in different areas for each nails
now do the same but with pink nail polish
lastly, apply glitter nail polish but don't use too much!
done! :)