First OTB Tournament

Touch move applies. Recording your moves isn't a requirement in scholastic events (at least not in my state) but if you want to review your games you'll have to do it. From what I saw kibitzing of any kind is frowned upon in scholastic events. Get your game done and then leave the playing hall.
Yeah in that section play on. If you get down to a king and rook vs. King ending don't resign just because there's no chance to win. Make them prove they know what they're doing. I'd be surprised if they did.

Rules:
-If you touch a piece, you must move it (or adjust it), unless doing so is illegal. Similarly, if you have released your hand from a piece, that counts as your move, and if you touch an opposing piece, you must capture it, unless doing so is illegal in the position.
-You must notate every move played in every game. If your opponent doesn't do so, you have a right to complain to the TD. I have seen some very low-level scholastic events where they didn't require this, but if you're in Middle School, they should enforce the rule.
-You can't say anything during the game (within reason, if your opponent's doing something really annoying or if you want to see his notation, you can whisper to him) except offering a draw and I suppose you can say "check" and "checkmate" (although at some tournaments it's considered rude to do this). It might be advisable not to say "check", since if you put your opponent's king in check and he responds with an illegal move that doesn't stop the check, he will be forced to use that piece to block the check, which could win you material or something depending on the position due to the touch-move rule (quite a possible scenario in a U1000 tournament).
-You can't do anything to annoy your opponent (other than play good chess moves).
Courtesies:
-Don't offer a lot of draws over the course of a game. That can annoy your opponents.
-Don't run around the tournament hall during the round. You can certainly get up from the table and walk around if you want, but don't do anything disruptive, loud, or noticeable which could annoy other players.
-Normally, I'd advise not letting your opponents checkmate you (i.e. resigning when you have a lost position) given that it can be interpreted as rude to play out a lost endgame. However, at U1000 level, I recommend not resigning since some of your opponents may even blow completely winning endgames (like they might stalemate you if they have Q+K vs K, or they might not know how to win a rook ending if they are up two pawns or more). If you really do want to resign and you are confident that your opponent will beat you from the position, you can do it a number of different ways, but the simplest is to tip your king over.
-Finally, make sure that all your results get reported to the TDs or the standings (every tournament does this differently). TDs get really annoyed about people not reporting the results of games.
What would be different between youth and adult sections? Probably not the rules, since the tournament rules of chess are generally the same in all tournaments unless otherwise specified by the arbiters/TDs.
I recommend bringing a water bottle and having it with you during all the games- it's never good to play thirsty. You can eat between rounds if you have to (theoretically, you could eat during a round, but this is pretty bad etiquette if it's a whole meal...maybe if you're just eating grapes or crackers or something that's not so bad). If you are going to eat a meal between rounds, I would say to avoid eating a large amount of food right before a round because invariably, the effects will kick in sometime in the middle of your next match and you will not be in the best condition. Try to give yourself a good cushion of time between when you eat your meal and the start of the game.
Get a good night's sleep (7+ hours) the night before the tournament. Very important for your brain to be in the best possible shape.
Finally, I have no idea what your skill level is, but if you win, lose, or draw, please be sportsmanlike. Always say "good game" and shake hands with your opponent after the game, and never be rude to someone just because you beat that person at chess. If you lose, it's alright to be upset at yourself, since chess is a very tough game and requires a high pain threshold. But don't make a scene in front of anyone else...if you are mad about losing a game, try to find someplace where you can be alone before you do anything. This isn't a problem for most people, since losing at chess is far from the end of the world, but since you're playing in a scholastic event, I just wanted to add this.
So I have my first OTB tournament next month. I'm going to be competing in the scholastic section of the tournament (K-8 U1000). I have seen a few forum posts about etiquette in these tournaments, but I thought I should still ask to make sure that there aren't any differences between the youth and adult sections.
Also, any general tips would be nice. I am a bit anxious for this tournament so any positive support is appreciated. 👍🏻