I haven't posted any of my water marbles yet, as I'm pretty sure the only good one I've ever done was my first, and I haven't bothered trying to do one since February... so here goes!
I tried a bunch of different methods with this and screwed a up a few (I actually had to start two nails over completely from scratch) but this is the end result. I really like them! It took about an hour and a half to do it all (re-dos included). I used American Apparel's Cotton for the base, then the other colours are American Apparel Raccoon, China Glaze For Audrey and OPI Greenwich Village.