The most important thing to remember in frisbee is that it is a game based on honesty and general good-spiritedness.  There are no referees so it is up to you to make good and fair calls and you should be able to expect it from your opponents as well.  So brush up on the rules.  Know whats in and whats out and what a foul is.  Above all know that if you ever have any questions don't hesitate to ask. There are no silly questions, we all learn from each other.