meditate first before playing
conditioning your mind
Absolutely this!
Some sort of deep relaxation technique applied throughout the session can work wonders. So many ways this can help:
1. A long tourney gets you tense, and uncomfortable - being half asleep means half the stress.
2. It looks like you are disinterested in the game - that can mean you are perceived as not 'being there to win', and so perhaps won't be taken too seriously as a threat by the right players.
3. It can help you focus directly before the game starts. I would chill at a lounge table, relax, and then quickly estimate amounts in my head: 26 slot machines; 7 waitresses; 74 light fittings etc. to help me focus on calculation and swift decision making.
4. You can handle threats of physical violence much better. This does happen BTW. Or is it just me?
5. Decision making is done calmy - which is good.
6. Prevents giving away
tells - a poker face, in other words!
7. Gives a perception of 'coolness' and arrogance, which makes you a target - which is good. If someone is 'out to get you' due to you being 'aloof' and 'chilled out' (and you need to be bought back down to earth, they think), they're going to play their hand wrongly.
8. It's easier to put out a subtle misdirection - such as checking down a set until the river like you have nothing - than if you're fairly animated. The slightest of 'tells' provided to an observant opponent by way of a 'disappointed' "check" throughout the hand and a very slight look of disgust on the turn will likely cause the opponent to be mistakenly confident in their hand, if they have one.
9. And in relation to this, relaxing at the table can make you more sensitive and aware to the other players' psychology, and so know how to handle them. No good trying to misdirect a player who's staring at their hand/flop, for example, and a nervous player may need to be shown weakness as opposed to strength. A bad player would usually require 'strong' play in most circumstances.
10. Wow! That's 9 good ones. One more: when you get in the money, you can be more rational with the sharing (in a tourney - that's what I know about) than if you were excited and keen to do a deal. You'll know what the calculation is, and what your share should be, so when you ask for 5% extra you'll get it, beause everyone else, apparently, wants the deal more than you - and they know how stubborn and 'correct' you are so nobody's going to argue about it. They 'know' you won't give a darn if you have to play on - and they just want the cash so they can go home. And it's not even though you WILL be 'pretending' to not care - you know you are good so are happy to play on if the deal isn't made. As a good player you will be somewhat 'entitled' to a bigger share due to your chips having more 'value' - because you play those chips better than, or at least as good as, the rest.
There are bound to be articles online for relaxing methods that will work for you. Be aiming for something that can get you relaxed in 5-10 seconds. I can explain my technique if anyone on here asks - it's very powerful and effective, and combined with learning about tells gives quite the unfair advantage.