:| HOW DO YOU DO THAT ALCOHOL THING. I AM FAILING MISERABLY.
What? The rubbing alcohol thing?
I do wet on wet for the base colour(s). Then, I have the alcohol in a little cup and I just dip my fingertips in it and flick it on the paint. To make bigger blotches, you can use a q-tip (I’m really not sure what sort of effect the alcohol would have on the bristles of your brush, so I wouldn’t actually brush it on, just to be safe), or just kinda splash it onto the paper from the cup.
Man, I dunno if I’m explaining this well.
And don’t worry if it gets somewhere you didn’t want it to be; it shouldn’t harm any paint you’ve already laid down, or the paper for future painting. At least, it hasn’t in my experience.
Try just painting some huge wet colourful swathes on a scrap piece of paper and fucking around with the alcohol. You can get some cool looking bubbly things by putting more concentrated paint around where you’ve already put alcohol, or whatever. Just try a bunch of things.