One of the biggest advantages I learned for stuff like this is the path tool. Rather than try to change the fills of the different shapes using the magic wand>fill, the paint bucket tool, or some other weird method, being able to import the paths from Illustrator into Photoshop and using the make selection tool is extremely easy and makes all of your lines look a lot cleaner at high resolutions. I found that the best way to do this was to set the stroke on your Illustrator lines to 0 before importing them. It also makes making clean masks a lot easier. Before, I would try to adjust the magic wand settings to get the best lines, but even with the best settings it was less than satisfactory. I tended to work a lot in Illustrator before importing things into Photoshop but now I can do a lot of the same things within Photoshop, which is pretty handy.
I'm hoping that I can use this path method along with some of the texture generation techniques that I used on the last master study to create more of these geometric studies. It's nice to be able to scan your own textures in, but when that's not an option it's nice to be able to create a 300 dpi texture to your liking within Photoshop itself.
It also might be interesting to kind of fuse these two techniques (this and the last post I posted) to add some texture to the flat colors of my sketchbook drawings.