If you speak to any sized group (or will soon), an investment of 18 minutes to watch this TEDx video is well worth it. Nancy Duarte (whose company has designed some of the most memorable slide decks in the world) shares how you must tell a story well. (Thanks for Kneale Mann for the find.)
Imagine that - speeches by Jobs and King follow the same trajectory.
Yours can, too. Help your audience imagine the world that could be and you'll engage them, inspire them, and have them telling others about you and your vision.
Main stages are for sharing big ideas, and there's no bigger idea than a glimpse of how the world could be.