People fear speaking in public more than death. (I’ve seen both things happen simultaneously in my workshops)
I have a theory based on my own speaking experiences. When I know the material, when I know everything about the material, I’m a pretty good presenter. But, when I’ve memorized the presentation, then I’m nervous. There’s a big difference between knowing and memorizing.
I get to know the material by discussing it, reviewing it, reworking it in rehearsals and presenting it over and over again —without a script—until I know it in my bones. I focus on the opening, because if I can get past that smoothly, the rest is cake.
You can’t avoid being nervous when giving a presentation, but you can feel very confident knowing the material better than anyone else in the room.