A speech written in your voice, slides that aren't a wall of text, a rehearsal plan that fits your lead time, and the nerves dealt with honestly.
The racing heart, the dry mouth, the certainty that everyone can see it. Nearly everyone gets it, and almost nobody in the audience can tell.
Stare, write, delete, rewrite, still unsure whether it's any good. The blank page is where most of the time and most of the dread goes.
They genuinely help with delivery. Most people face a big speech with no help at all because that's not a realistic option.
Twenty run-throughs in front of a mirror mostly rehearse whatever you already do wrong — including the timing you never actually measured.