Eh, you'll probably never feel prepared enough. I probably put in around 9 months with around 3 months of "want to kill myself" effort.
We had Osler audio and notes through our program so I used that, the Lefkowitch, the new AP CP question books, though the CP one is ridiculously difficult. Also the compendium. We also used Study Blue to make flash cards and spread them among our class, so when I got desperate for sunlight, I could do flash cards on my iPad at our local outdoor bar. I used the Blood Bank guy lectures for that. I drove to Tampa, so listened to him all the way down. CAP was in the middle of all this, so I deliberately did a 8 hour cyto review course at the meeting since I figured it would be helpful and it was, so if you have a conference during that time period, sign up for lectures that are general reviews on high yield subjects.
I passed, as did my whole residency class. I'm not sure if that means I squeaked by or overkilled, but there's likely no amount of preparation that won't make you feel gut punched when you leave.