Know critical engine, what Vmc is and what the effects are on it by different factors - eg aft C.G., density altitude. Know all the aerodynamic factors acting when an engine is lost. For the flying part, just keep your head in the game. My DE turned the fuel selector off and then started chatting with me about stuff as I was setting up for the ILS to try and catch me off guard. Fly the airplane first, have your checklists handy, but don't get them out until you have the airplane under control.
The only thing I kinda screwed up was my landings. He said I landed like a rookie...which with 8 hours ME I am a rookie. I followed the glide slope until I had the runway made, and then I slowly started bringing the power back and touched down about 500' down the runway...just like I've always done. He wanted me to follow the papis all the way in and set it down right on the aiming point markings...like the big boys do it.