Starting flight school this Saturday. What to watch out for and how to be efficient?

For efficiency, try and understand what your instructor has coming up for you, and chair fly as much of that as possible prior to your next lesson. Ask them if they are following a syllabus and whether you can see what the next couple of lessons are. Then chair fly as much of that as possible. For example, if your instructor says you are going to be working on steep turns next lesson, ask them if there are any specific altitudes/power settings/air speeds/landmarks they like to use. Then chair fly that. It might look something like: clearing turns, call on frequency, pick landmark, ensure maneuvering speed/power setting, firm bank into the turn, maintain back pressure, ~200 power, couple of good turns on trim wheel, ensure nose is slicing the horizon, double check angle with attitude indicator, double check maintaining altitude, maintain turn until 10 degrees before landmark, roll out, reduce power, reset trim, double check recovery. If this sounds like a lot, it is in the beginning. Hence why you want to get your head wrapped around it before you have the yoke in your hands. Then just do this for everything they want to cover in your next couple of lessons. Easy right? Also, probably wouldn’t hurt to understand common alternates based on if your airport is busy, or for some reason not busy and you want to jump in the pattern, or if the practice area is super full, or, or, or. Basically do what you can to stay ahead.