This is mostly for AP, of course: Before trying to read all of Rosai, flip through the whole book and just look at the pictures. Building a huge mental library of images of various tumors and entities is very helpful. That way you will hopefully recognize a rare case when you stumble across one. You can always look it up and read the details about it at that point. But it's hard to look up an unknown tumor in a book based just on what it looks like if you have no idea what name to potentially give it. In the same vein, spend lots of time looking at recut study slide sets of rare and common cases.
For all residents: Get involved in the CAP Residents Forum (RF). You can volunteer to be a delegate for your program: residents.cap.org. But even if you aren't a delegate, anyone can attend the RF meetings held the Sat before CAP and Sat before USCAP each year. Being in the RF was so much fun, and it was a huge benefit to my career. It also indirectly resulted in my current job (I got to know Jennifer Hunt, my current department Chair who recruited me to UAMS, during my time as Chair of the Residents Forum).
And in general, from day 1, network, network, network. Attend as many meetings as you can, get to know everyone especially your local private practice pathologists, build relationships with everyone. Don't burn any bridges.