Practice, Persistence, Perseverence.

Oh no! I found out this gray
had a little bit of an accident...

Or, alternatively, "I refuse to suck at this". I speak of course, of the nail art style that kicked my butt which was water marbling. The one that got away. My white whale, if you will.
I've complained about it on my previous post about water marbling, and one of my issues with the method stemmed from the frustrations of a lot of polishes not lending themselves to the technique (they wouldn't spread in the water properly). The post reads as pretty bitter.
In my practice runs I had thrown polishes together not really realising not all of them would simply work well together no matter how much one tried to telepathically will them to. I concluded that what I therefor lacked was knowledge.

And that knowledge would only come from testing and trying what works and what doesn't.

Testing in progress.

I'd decided to create a little database (read: list) for myself to work with the problem I had of not knowing what colours I had to work with that would lend themselves to marbling. So that in the future, I would know what I could grab that would work just fine and not have to deal with the disappointment of "oh, x and y would look great together!" only to realise those polishes had other ideas.
To limit wasting a bunch of nail polish on experiments, I mostly used my white nail art stripers (they do spread) that I don't use much, and paired them with the colour I wanted to try.

In italics means 'will spread, but not great'.

So, here is what I have so far. I was surprised to find that the will spreads outnumbered the will nots.
Unfortunately I still don't really have a large pool to choose from but if I just test some polishes every now and then I'll expand it quickly enough.