Professional athletes practice. They practice all of the time. Even after playing 6 or 7 games in a row, basketball players come out the next morning to practice.
If you’re making a presentation you need to practice. You need to think through all of your plays. How are you going to open? What is the single big message you want people to take away? How will you summarize and what action will you ask of the audience? Then you need to rehearse all of this in front of real people.
Now you’re ready for game day.