I'm going to spare all the details and just say, I have no clue how to use it and I've been trynig to figure it out lately.
All the tutorials on the interweb are complete crap. They say things like "Go to the layering tab and click the gradient release button, then choose your saturation setting and set that as your third layer." AS IF I KNOW WHAT ALL THAT MEANS. I need a tutorial that says stuff like "See that button right underneath that button that looks sort of like some old lady's arthritic hand? That's the text button."
I do know, however, how to download and use different brushes. It's so much fun. I don't really know how they'll serve any purpose in the future, but they sure are fun to work with. Here are some I've been playing with. (Click any picture to see it in better detail.)
Some dead trees. Looks pretty sweet, no?
These were labeled "Japanese Foliage", but they look more Hawaiian to me. Either way, they're cool looking.
I got these because they remind me a lot of John Mayer's Jimi Hendrix Monterey Pop Strat guitar, which is my favorite of his.
My mom really liked these. (Of course, she's impressed by anything computer programs can do, so...) Wouldn't these look pretty on wedding invitations?