I have just completed (and passed) my peds CCRN. Several nurses on my unit have done the the same. We found it very helpful to attend a systems review class.i think that it gave some useful info and study tips. I also read Core Curriculum for Pediatric Critical Care Nursing by Slota. There are also Pediatric sample tests available with explanation. I think that overall, my experience at the bedside was my greatest tool. Good Luck