I found the review course that ASPAN offers helpful when I was preparing to take the CPAN. It was EXPENSIVE but the handouts were fantastic. The other poster is correct though, that much of it is critical thinking. I also found ASPANs practice tests helpful. Its a bit of a rough test, and there arent as many prep materials around as there are for CCRN, but totally worth it to make yourself marketable in our area of practice.