I do this from time to time and I can actually get some decent wear time out of them if I'm careful. :)
These are quite a bit longer than I'm used to, but I'll see how long I can handle them before I need to file them down. So far so good!
I started with a white base on the nails. For this, I used China Glaze White on White. Just one coat, which I let dry most of the way. For the marble, I alternated Rimmel Posh Pink, OPI Rumple's Wiggin & Butter London Slapper. Slapper wanted to spread out a lot, so I had to be careful with it. First few tries weren't great (I have those on my right hand, lol) but they weren't bad. Once I mastered the swirl, oh man...
I'm officially in love with doing water marble now. *__* I finished these off with a coat of Model's Own Indian Ocean (pictured) which really made them pop. I love this polish so very much.
One of the biggest tips I can give those who want to do water marble is this: use hot/warm water and clean the water once every few nails with clear polish. I also dumped my water after five nails and started over. Living in Florida and not having a water softener, I have fairly mineral water so I also had to wait for it to settle just a bit before I began (the few little spots are from trying to early).
I plan on doing a set of water marble with art for St. Paddy's Day, so stay tuned for that! I'm also going to start selling these on my Etsy when I get the supplies I need. :)