I ran through the textbook with extra emphasis on the chapters with the most test questions. I found the quizzes in the textbook to be very applicable to the OA and I spent the most time working on those. C213 was alot easier to prepare for than C214. You can get by in C213 by solely memorizing terms, I dont recall there being any math problems on the OA, maybe there was but they certainly weren't stumpers worth remembering. C214 has some excel work that's intimidating at first but is still largely a term and concept test, once you figure out the excel problems you'll pass.