Here's some of my tricks - even a few dirty ones.
Sorry I can't give them all away, at least at once.
Most of the tricks will help to focus on the shot or refocus or mind onto something else. Some of these are contradictory, it really depends on what works for you. The other trick focus on the game and or shot tempo.
1)Pre Game warmup
When I was played my first couple tornaments, I always tried to play at least 4-5 holes before the tornament starts...besides getting rid of the jitters it also helps you warm up ,clear your mind, and focus on your game plan.
2) Have a game plan
Going into a tornament or any round you should know exactly how many and which holes you can birdie. Use this to calculate your absolutely best possible finish, but don't play for the perfect game, instead set a goal a few strokes higher. This way you won't start crumbling after the first or second miss.
This also lets you work a plan to achieve the goal, mini victories can give you confidence. It also will let you know which holes you really need to focus on and which holes you can afford to relax on. This is very important as the mind has a hard time maintianing continual focus.
3) Know your limitations...this kind of goes along with setting up the game plan...but it's more of a hole by hole reminder.
If a hole farther away than what your max distance, don't expect to suddely throw the extra 50ft. on the day of the tournament. Some holes are simply going to be out of your range, so their is no need to put everything you got into it. Take alittle bit off and make the safe consistant play. It's OK to play for par
4)Find something else to focus on....like annoying your opponent. I don't mean throwing things at them or yelling as their making a shot. The goal here is subtle. Remember their suffering their own demons too. Sometimes just a few minor things will send them over the edge.
One thing that really seems to work for me is trying to disrupt their game tempo. Taking a long time to set up for a shot or even walking to your disc-reapeatedly this can really bother some people.
The oppisite is also effective, some people don't play very well if they feel their constantly being rushed or pushed. Reaching their lie quickly and first while continually waiting on them can sometimes disrupt their game. It might sound a little underhanded or unsportman like but controlling the tempo will win you games.
5)Lastly, if the shot does't "feel" right, nobody is forcing you to shoot it. Step away, shake it off, and reset. - Also can be used to disrupt your oppenent.
6)Don't worry about the score, try to play as if your only one stroke down....this helps to maintain focus. But be carefull it's hard to maintain this type of focus for more than 9 holes.
7)Setting up a routine and rythm will help keep your mind off of the shot.
Alot of players will play with a different tempo during casual play versus a tournament round, this is why they have great games by themselves but suffer while playing in groups.
You need to focus on your shot tempo, count it out if you have too, just be consistant. This can help you identify if your rushing the shot or concentrating too much. Ideally, on the big shots you should just focus on just the shot temp and body motion. You need to be a little bit self aware here too, just to make sure someone isn't trying to mess with your game / shot tempo.
Sorry if this is a little jumbled,and incoherant -it's late for me.