I've marbled at home using a kit from etsy. You float paint on top of thickened water, and use combs to swirl it around. Then you take a "print" by laying paper on the surface.
Diane demonstrated a number of patterns before setting us free to make our own designs. I came home with about two dozen sheets of marbled paper, and now I'm itching to make more.
With the intricate marbling combs at hand, I feel obligated to produce elaborate patterns. But I'm most drawn to marbling done with abstract, amorphous blobs of color.
Side note: I used "amorphous" in a sentence at work yesterday and someone asked me if I made it up. I didn't; I swear.
I think I'll try a more free-form approach this weekend. I've been collecting marbling inspiration on Pinterest. All that's left to do is mix up a batch of carrageenan and drop the baby off with my in-laws.