Let me tell you what worked for me, as far as learning the aircraft systems. I could never read the manuals and fully understand the various systems.I did this...take a piece of paper and draw a system...example..the fuel system. Do it enough so that you can take a drop of fuel from the tank, through each and every filter, pump, check valve and crossfeed in the system. Then do the same for the hydraulics and all of the others. If I could visualize the system, I could "get it". Dazzle them with your knowledge of the systems. Good Luck....