One of the things most people are missing from their chairflying is the randomness of other people throwing random situations at you. This did not become readily apparent to me until I got to Kingsville. You need that extra person to throw in the random, "Uh oh, you just hit a bird in the pattern, what do you do now?" It forces you to think on the spot, because you didn't expect it. It also teaches you new things that you should be thinking about while flying particular phases of the flight (that whole concept of being 10 miles ahead of the jet). I'm telling you, it's a lot harder to react when it's random, but it will teach you to think on your feet, and once you get good at it, you will be a lot more confident in the plane.
One of the things that helps me out the most when I fly now is always asking myself , "what if?" Where is the nearest divert? Where would I go if I hit a bird RIGHT NOW, if I got an Oil Pressure light, or a fire light. Constantly be developing a plan, that way when it happens, you don't have to think, you can just react. (obviously no fast hands in the cockpit, you don't want to inadvertantly turn a small emergency into a big emergency) Not to mention it develops good habit patterns of being ahead of the plane, especially when you're flying lead for someone else. Good luck, man, you'll do fine.