I think the biggest problem I had with Fundies was decision making. I had problems with things like having one teammate cork and another swim off into the murk, and I was team leader and had to figure out who to stay with and who to follow. Same thing with descents -- one buddy would plummet to the bottom, the other had ear problems -- who to stick with? Holding depth for a drill when my buddies were yoyoing was very difficult, as well.
I think one of the best things you can do before a class is dive with your classmates, so you all have an idea of your strengths and weaknesses before it starts.
I think one of the best things you can do before a class is dive with your classmates, so you all have an idea of your strengths and weaknesses before it starts.