I'm doing a hybrid version this year, using up a lot of my stash and making it my own. I decided, in the interest of saving myself a little time, that I would make a template for 3x4 cards using my favorite scrappy tool, the Silhouette. And while I have the SD and not the current 12x12 Cameo, the same instructions can be applied to the 12x12 format. You will just get more cards on each page with the 12x12.
To start, open up your Silhouette workspace: (Click on any image to view larger).
Send to your Silhouette and cut away! Or, "Save as" to your library and use over and over AND over again! Happy Project Life-ing!
Email me or comment here with questions.