Less CAT exams, more learning. I only took three CATs in my 9 months of GMAT prep. A full-length test is a good progress marker but you're not going to learn as much from it as you could by working some problems and understanding why you're missing the ones you're missing. The rest of the time I spent going through my
MGMAT books and learning how to actually work the problems, memorizing all the important formulas and processes, and addressing your weaknesses.