So, I'm still working in CS5, and without the pattern-making tool I was having such a hard time visualizing how it was going to come out that I made a few changes.
First, though, I was delighted to pull my own alcohol inks back out after a year or two and draw a few things.
Then, instead of working on a 12x12", I changed the size to 24"x24" and used a 12" guide in the middle. This really helped me see the whole pattern tile without confusing myself about what I had to move to the opposite side. Also, CS5 doesn't do the math for you, so out came the handy dandy computer calculator... ;)
I had to flatten the image, resize it to 12", then used the marquee tool to highlight the actual pattern (the marquee snaps nicely to the guides, thank goodness). Then Edit-->Create Pattern. If you want to move the pattern around on the page you have to fill a larger square, then crop it to what you want.
Anyway, I had a really hard time deciding what background would be good, but I used the different adjustment layers to play around with the color. That was SO fun! And I ended up really liking the monochrome-ish version a whole lot... Thanks again Sandra for a really great class! =)