First, I commend you for seeking knowledge! You’re going to absolutely love the expert server!
The expert server is the true “simulator” server for IF.
Everyone agrees following ATC instructions is a big deal!
But in order to do that, you have to understand each instruction. Understanding things like: entering and flying in a pattern, proper decent speeds/altitudes and maintaining adequate separation between aircraft around you are “must know” knowledge while flying on the expert server. Same as in real world, not knowing the rules is not an excuse for not following the rules.
I recommend spending these next 2000XP familiarizing yourself with understanding when to contact what ATC (ground/tower/ctr/etc.), and how to properly communicate with ATC. This is the major “night and day” difference between the casual/TS1 server and the expert server. Learn how to effectively communicate over Unicom as well. (ATC aren’t the only ones on Expert that can report you.)
In addition to understanding how to utilize ATC and Unicom, it is very important that you know the dynamics of your particular aircraft you fly while on the expert. Things like proper approach protocols per your aircraft, decent speeds and properly intercepting the localizer will help you in maintaining a clean record. I don’t recommend flying an aircraft you’re unfamiliar with there. That is what the casual is for.
Hope this answers some of your questions but doesn’t scare you away lol. I look forward to flying with you on the expert!