When they practice they are focusing on the minute detail. They are focusing on getting every component correct. 2 weeks ago I spent some time with a group of people learning advanced presentation skills. They all had a high level of skill to begin with and they were training to get various aspects of their presenting even better. During and after the week these people would be hoping to transfer the knowledge they accrue into working memory of their frontal lobes.
Then, when they are on stage giving presentations they will focus on one or more of these components that they have been focusing on during training. This enables them to go into ‘the zone’ and avoid chocking under pressure.
This is one of the biggest differences between amateurs and professionals. The amateur will focus inwardly and the professional will focus on a task to be done.
The concert violinist Nadja Salerno-Sonnenberg says “My approach to performing is: The time to be careful is when you prepare. But, in performing, I say, take a chance, go for it,”