Playing in Tournaments is truly a different breed of game then normal league nights. The only real way to be prepared for a tournament is having played in many. Staying focused and realizing that you are the one at the table playing your game. Tournaments can be a stressful time but if you take steps by continuing to practice and stay healthy (mentally and physically) will greatly improve your chances of doing well.
I came across this article from the PoolDawg Library that I think is a good read and has really good thoughts on Tournament Play. I have copied the article below but you can go to the PoolDawg website and see the original post here Your Guide To Playing in Tournaments by Liz Ford on the PoolDawg Webiste.
Your Guide To Playing in Tournaments
by Liz Ford
A great many players who play in friendly practice, leagues or at the local bar on Friday night, can be humbled in a hurry when it comes time to play in their first big tournament. Playing successfully in tournaments requires physical skills, which are gained from practice on the table, but there's another skill-set, one of self-management, that can highly enhance both how you play and how much you enjoy yourself. The following tips represent a well-rounded approach for improving your tournament experience.
1. You can't cram for your exam.
The time for learning and sharpening your game is in the weeks and months before a tournament, not the days or hours. Some players even take a short break before an event to ensure that they feel fresh and relaxed.
2. Being nervous doesn't mean that something's wrong.
Almost all competitors, both new and experienced, feel nerves. You can take the edge off with breathing and relaxation, but nerves aren't something you can, or want to, make disappear all-together. Having some nerves gives you energy and focus to get the job done – without them you'd feel flat and unmotivated.
3. Know what you can control and what you can't.
You can only control your preparation for an event, your choices during play and your attitude, so these are the only productive places to direct energy. Time spent worrying or fixating on your opponent's luck, the condition of the tables or other things you can't control will only frustrate and exhaust you.
There is plenty more tips in the article so please follow the link above as Liz put in good effort on the article.