Before the game itself, it is imperative to concentrate, mobilize your thoughts for the upcoming game, remain vigilant and carefully monitor everything that happens. The main task is to think only about poker, trying to get out of my head all thoughts not related to the tournament. It is important to be able to adapt to the current situation, to have your own strategy. If your thoughts are occupied with other worries, then you simply cannot fully control all information about the game, which means that you cannot fully assess the situation at the gaming table.
Personally, I begin my inner preparation with a little meditation. Then I direct all my thoughts exclusively towards poker, which allows my brain to tune in to the game. Sometimes you can watch an interview with a reputable player about a game or read a couple of articles in a poker magazine.