I don't know how well this will translate to your situation but here's what I focus on:
1)
Playing more games. A mix of more serious and faster games should work fine. You can also take this opportunity to practice and prepare your favourite opening patterns.
2)
Analyse games. Preferably with AI or a stronger player. It's also helpful to keep track of and to practice your common mistakes (I use AI Sensei for this but I'm sure you can improvise some sort of system).
3)
Flood my brain with good moves and shapes. I rarely replay professional games but I like watching pro game analyses on YouTube (Michael Redmond, Baduk Doctor, Go Pro Yeonwoo, Dwyrin and occasionally some others as well). Watching stronger players play and comment their games is also helpful, though the quality of those games will be lower.
Physical preparation:Try to get enough sleep and rest.
Make sure you eat and drink enough during the tournament. I always have a water bottle and some emergency snacks with me.
Ironically, one of the best ways to prepare for a tournament is to regularly attend tournaments. Whenever I don't do that I find it much more difficult to stay focused on the games and get tired more easily. Not sure how to get around this issue but perhaps you could try simulating the tournament schedule once or twice to build up the endurance.
Psychological preparation:Others have already given you a lot of great advice, I'd just like to stress here the importance of patience and of keeping a calm mind. Here's some of my most important mantras:
Focus on the current move, not on winning the game.
Focus on the current move, not on past mistakes.
Focus on attacking, not killing.
Counting is important. If you're ahead, simplify the game. If you're behind, make it more complicated.
I've checked the game you posted and saw that you went a bit off-kilter a few times when trying to attack your opponent. Generally, most kyu players and a fair amount of dan players will defeat themselves if you just let them. Just be patient and make sure your position is strong. Perhaps you could play a few games where you just focus on building a strong position and on reducing & enclosing your opponent's groups. I've tried that a while ago and surprisingly won a lot more games then when I was being more aggressive.