The following painting was mostly done with a brush which gives a little more control but I don't think it's nearly as pretty.
The background was done by dropping different inks onto the Yupo, then the painting was sprayed with plain rubbing alcohol. I don't have a lot of colors so the coneflower center didn't come out as dark as I'd wanted but I was able to darken it some with some Bic colored markers that I had. However, I think that ruined it so I'm not posting the revised painting!

There are tons of tutorials for the inks out there with a lot of them on YouTube. Some I'd like to try are:
https://www.youtube.com/watch?v=icjFa1UsaDg
https://www.youtube.com/watch?v=gAEhf24ZczI
https://www.youtube.com/watch?v=9p9D0KVWswk
The above shows what can be done.
And I definitely want to try this one: https://www.youtube.com/watch?v=6r6yiPWJ41s
Hope these show a little of how to work with the inks. If none of these appeal to you, just look around the internet!
So many things to try and so little time!