In the USA you'll likely want to bring your board, pieces, clock, scorebook and at least 2 pens or sharpened pencils. You'll also want something to pass the time between rounds such as a novel, or games on your phone or whatever.
Somewhere between 1/2 hour before and 10 minutes before the round is scheduled the TD should post hte pairings. While you're waiting for the pairings to be posted hang out in the skittles room and meet people, play bughouse, or whatever you want to do in order to relax.
Once the pairings are up, see if you're black or white, your board number, and the name of your opponent. Write that information down on your scoresheet. If you don't have a scorebook, they usually provide scoresheets on site.
Make your way to your table. The tables will usually be labelled with board numbers so you can easily find where you are located. If you are black you will be expected to set up the board and clock. If you don't have a digital clock, ask your opponent if they have one and use theirs. No matter whose clock you use, make certain you are familiar with how it operates, including how to pause the clock and how to add time to either side in the event of penalty.
Introduce yourself to your opponent and make small talk until the start of the round.
Shake your opponent's hand and begin play. You will want to write your move down AFTER you make it on the board, not before. Do not make any marks on your scoresheet beyond your move -- many coaches mistakenly tell their students to put all kinds of information on the scoresheet, but this is not legal. Only the move information may be recorded, and it must be recorded after the move is made, doing it before hand is considered a form of "note taking" and a very hard core TD might penalize it (though at an u/900 unrated that is not likely!)
Once the games are underway you don't want to talk to your opponent at all. Doing so is considered a distraction and is very much "unsportsmanlike" behavior, even if you are complimenting them on a good move.
When the game is over, ask your opponent if they would like to go to the skittle room and analyze the game. Do not analyze the game at the playing table, as this can be a distraction for those around you who are still playing.
If you have a question, you need to pause the clock and raise your hand to attract the TD or one of the assistants.
You may wear headphones, and yes, many people do that. Personally, I'm a fan of earplugs since I don't like listening to music, but stray noises do distract me.
Make sure you let your opponent's know it is your first tournament. You'll find most people will be quite helpful if you have any questions or issues.
Good luck, make sure you let us know how you did!
It's unrated / U900 (beginners tourny)
What is the normal / courteous way to go about things?
Is there any talking to your opponnent, like "nice move", "I didn't see that", "OUCH!!" ?
If I have a question for the TD do I pause the clock? or ask TD to pause clock?
Are you allowed to wear headphones? Do people really do that??
Which opponents set is used? Is it the black pieces since white has first move?
Am I missing anything?
Thanks in advance!