A keynote is not a long talk; it is a short talk with the confidence to repeat itself. The best keynotes say one thing, three ways, at rising stakes — and they trust the audience to assemble the meaning. Read any great conference talk and you will find the same skeleton: a personal opening, a promise made explicit, and a closing image simple enough to tweet.
The through-line
Every element in a keynote either serves the through-line or dilutes it. Before adding a story, a stat or a slide, ask which sentence of your talk it strengthens. If the answer is "none in particular", it is a second talk trying to sneak into the first.
Examples to study
The keynote examples in this library were written to be read and raided: a product launch that sells a habit rather than a feature, a public lecture that turns a failed Mars lander into a lesson about honesty. Steal their moves — the openings, the transitions, the landings — not their sentences.