I used OPI Alpine Snow for a base coat. Then I just put a small bit of paint in an old ice cube tray and add a few drops of water to thin it out. Then use a regular paint brush and hold it over your nails and tap it until you like the way it looks. Wait until the acrylic paint is dry before attempting a top coat - I learned this the hard way!! It will smear all over the place and you will have some funky looking nails! Here are my instruments of torture:
Here is the awesome mess that I made! You could tape off around your cuticles and that would make the cleanup a little easier if you want but I didn't!!
And here is the finished product! I'm thinking of making a video on this technique, what do you think, should I? I don't know, maybe paint splatter nails are "over," but I still like them and I never claimed to be fashionable!
My next attempt may have to be a water marble but that may be a while off - the idea still scares me a little bit! :)