So, I know a brother he learned how to swim my telling himself, today I’m going to try to drawn (as you know when you try to dive, the water will naturally let you float) so he trained his body not to panic in water. So, the way you suggested is the same, say you are worried people to laugh at you giving a public speech. So, you tell yourself, I want to hear how loud can they laugh and any how many mistakes I can do…. then you won’t worry about making mistakes.

The idea is to put your focus on the real goal (and everything to get the goal achieved), while setting yourself free from worrying about possible mistakes.