Oops not analyse I meant an.
I'm going to analyse OTB tournament tomorrow. Any tips?
Outdoor physical exercise, sleep well, eat light, visit the rest room before you play, stay hydrated.
Do not bring any phone, watch, or pen: that may get you disqualified.

Outdoor physical exercise, sleep well, eat light, visit the rest room before you play, stay hydrated.
Do not bring any phone, watch, or pen: that may get you disqualified.
The first part is good advice, but the second part sounds too harsh. Only high-level FIDE tournaments would be this strict and disqualify someone for something like bringing a watch.
I play in USCF tournaments and watches are fine (I assume you meant smart watches which could connect to the internet/a chess engine, but wrist-watches are probably okay). I recommend bringing your own pen. Tournaments may provide a pen for you to take notation, but they might also have a bag of pens for a bunch of players and having your own pen is just one less thing to worry about. A phone is a little more tricky, but where I play, tournaments usually allow phones as long as it is kept outside the playing hall, or stored somewhere secure which you don't access (like a backpack or briefcase etc.). Just make sure your phone is turned to silent. Your phone ringing mid-event and distracting players will probably get you disqualified.
All of these "little things" are not important in my opinion. Right now, your number one goal should be to just enjoy the atmosphere of an OTB chess tournament and to try to play your best. Everyone plays worse in their first several tournaments and it is common to be nervous. Lighten up and have fun
Get a good night rest if you can, eat a good breakfast and take your time on your chess moves. OTB tournaments tend to be longer time controls where many newer players have a tendency to move a little too quickly.
@4
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11.3.2 During a game, a player is forbidden to have any electronic device not specifically approved by the arbiter in the playing venue.
11.3.2.1 However, the regulations of an event may allow such devices to be stored in a player’s bag, provided the device is completely switched off. This bag must be placed as agreed with the arbiter. Both players are forbidden to use this bag without permission of the arbiter.
11.3.2.2 If it is evident that a player has such a device on their person in the playing venue, the player shall lose the game. The opponent shall win. The regulations of an event may specify a different, less severe, penalty.
11.3.3 The arbiter may require the player to allow his/her clothes, bags, other items or body to be inspected, in private. The arbiter or person authorised by the arbiter shall inspect the player, and shall be of the same gender as the player. If a player refuses to cooperate with these obligations, the arbiter shall take measures in accordance with Article 12.9.'
https://handbook.fide.com/chapter/E012023

@4
'
11.3.2 During a game, a player is forbidden to have any electronic device not specifically approved by the arbiter in the playing venue.
11.3.2.1 However, the regulations of an event may allow such devices to be stored in a player’s bag, provided the device is completely switched off. This bag must be placed as agreed with the arbiter. Both players are forbidden to use this bag without permission of the arbiter.
11.3.2.2 If it is evident that a player has such a device on their person in the playing venue, the player shall lose the game. The opponent shall win. The regulations of an event may specify a different, less severe, penalty.
11.3.3 The arbiter may require the player to allow his/her clothes, bags, other items or body to be inspected, in private. The arbiter or person authorised by the arbiter shall inspect the player, and shall be of the same gender as the player. If a player refuses to cooperate with these obligations, the arbiter shall take measures in accordance with Article 12.9.'
Maybe it wasn't explained clearly the first time. The FIDE handbook seems to confirm what I said about those things not disqualifying you. It seems that refusing to be inspected (or accessing where you store electronics which could use a chess engine) is what may get you disqualified.
This handbook is strict for a reason; we want to protect the integrity of chess and deter cheaters, but for someone who is going to their first ever chess tournament (or even first several events), it is more beneficial to make them feel more comfortable and less nervous.
Teaching them strict regulations might be well intentioned (and objectively true rules), but not necessary to cause more unnecessary nervousness. The chess player should just try to have fun and enjoy the new experience.
Any tips?