Having worked now at five different tournaments, here are a few things I've learned:
* Never assume the published standings are up to date... you may think you're close to qualifying for the semis and then all of a sudden you're way down in the rankings... many times the standings are not up-to-the-minute, so you have to be patient.
* Respect the TILT!
Pay close attention to how sensitive the tilt is on the machines. It can vary dramatically.
Some people don't realize that TILT does different things on different machines. If you're playing in an EM tournament on ball 1 of 5, and the ball is going to drain and you manhandle the game to see how sensitive the tilt is, don't freak out when that's the *end of your game*. Some older EMs tilt and it's "game over" not "ball over."
When you're playing multi-player during a tournament, RESPECT THE TILT. You can become disqualified if you "tilt-through" to the next player and affect his ball. You'll lose the match and piss everyone off.
* Don't be afraid to ask fellow players for advice, but don't be surprised if they aren't terribly helpful. I've met some players that want to be "in the zone" and don't want to talk to others, and some who are more than willing to share what they know about the game. Some people are more competitive than others, but don't let that discourage you.
* On some machines you can press both flipper buttons to display the last score so you can take a picture
* Have fun - don't take the competition too seriously.