Visualisation or mental rehearsal is a powerful way of preparing for an event.
It starts with having experience of the event in real time, so, for instance, competing in an athletics event at a familiar venue. Remember the Internet allows us to see venues we haven't visited before and in this way become familiar with them.
Visualising your performance prepares your mind, body and soul for the coming event.
You start with quietening your thoughts. Sit or lie down in a quiet space, close your eyes and breathe normally.
Focus your concentration on your breathing and the action of inhaling, feeling the soothing inbreath; and then exhaling slowly until the breath disappears. Repeating naturally.
If thoughts appear in your mind allow them to pass through without any analysis, say "Hi thought" and away it goes, blown away with each exhalation.
As your thoughts disappear, keep focusing on your breathing and your mind gradually becomes quieter and a space onto which you can imprint a film of you successfully performing your technical and tactical processes.
So now let's develop the film; see yourself arring at the venue of the event. Breathe in the familiar atmosphere and exhale any anxieties.
See yourself competing as you move towards the start and go through your setup. Then at the sound of the [gun for track] [horn for field], see yourself successfully going through your technical processes and tactical strategy, which you have been training to use. It is important to only reproduce your training performance when visualising competition performance; this is because you need to believe in the realism of the image you create in your mind.
Visualisation is about success, it is a powerful way to improve performance, hence you must only visualise success to provide only positive mental imprints.
Breathe and remind yourself with self-congratulation that it is like you to perform well.
You are the success you believe yourself to be.