Go in an even-numbered group.
Go early, to avoid disappointment. (As in, before noon.)
WAIT till the woman brings beer to the table. (And don't mess with her, she's stronger than you.)
Don't poke fun at large men in Lederhosen.
Do not try to break up the married-women fights.
Do not break into a chant of Eng -el - land Eng -el-land Eng-ge-laaaaaaaaaaand
Don't eat the sausages from the sausage stalls. They are crap.
Don't go on the rides after 8 litres of beer and the crappy sausages.
Do not go into the boxing tent after 8 litres of beer and the crappy sausages. The polish pros are even stronger than the beer women.
Do not attempt to pick up a chick in a dirndl. Not going to happen.
Bang beer mug on table when the others do.
Sing the English words to the songs. No one cares anyway. (For example: "And it's no nay never, (bang beer mug four times) no nay never no morrrrrrrrrrrrrrrrrrrrrrrrre, shall I play the wild rover, no nay never, no more.")
Stay away from Lowenbrau, and especially Hofbrau above all. Their beer is crappier than the crap sausages, and no-one from Munich drinks that crap anyway. Try to get in at the Augustiner tent if you can.
Have someone in your even-numbered group hold your seat when you go to the can. (Actually, an enormous trough. Close your eyes and think of England.)
Don't talk about the war.