As someone who participated on a lot of OTB tournaments, won 4 district tournaments, and provincial 2nd. My BIGGEST advice is to remain calm. You got time, it is a classic tournament. Even if you know your next move DO NOT make your move immediately. Lasker has a great saying about this: "I hate finding good moves, because when I find one I have to look for a better one" though the English translation is a bit simpler. The Point remains the same. Second of all, if you already know some key opponents you will face and you have their chesscom username. Analyze their games, which openings do they like to play? What openings are they weak against, etc. BREATHE when you lose a piece or have an advantage do not get too worried or excited, that will throw you off your game. Chess in that regard is also a game of composure. Do your homework, make sure to play some classical games online before the tournament. Those few days can make a huge difference right before the tournament but don't burn yourself out. And take notation, idk if you do this right now but taking notation of your games and then analyzing them later or even in between rounds will help you. But do not lose your composure because you lost a piece or even a game. Always keep calm, even if you can not get first place it is not the end of the world. We all play chess because we enjoy it. Waiting to hear good news man. Good Luck!