First China Glaze Strong Adhesion Base Coat then 2 coats of Sally Hansen Xtreme White On. I also applied Vaseline around each finger so at the end the nail polish would be easy to take off. (some people use tape but i didn't have any)
You need a small container filled with room temperature water, make sure you have all the nail polishes open and ready to go. I used 3 drops of Sinful Colors Innocent, 2 drops of China Glaze Shocking Pink Neon, and 2 drops of Sally Hansen INSTA-DRI Snappy Sorbet.
Then take a nail stick or tooth pick... anything really and swirl the nail polishes around into the design you want
Before you pull out wait a few seconds and then take the tooth pick or whatever your using and swirl it around in the water to pull out all the dry nail polish around your finger
It can get very messy so make sure to use tape or Vaseline :]
Add a top clear coat and clean up around the nails with fingernail polish remover.
For the first time ever doing water marbling I'd say it turned out pretty good !