• Speak directly to the members in your audience; look at a single person at a time, focus on them, and talk to them like you would have in a normal face to face conversation. This will help you see if they are following along.
• Listen to your audience. It's best to have a silent audience. If the audience is dead silent, that usually means you are on track.

Facts with no meaning are dull.

Tie every fact (or set of facts) you present to a story, to emphasize why knowing these facts will bring value and will influence the perception about the world of the people listening.

Your speech should be a process of truthful exploration, almost like a journey you are taking your audience along.

Don't aim for an overprepared speech and leave space for play and exploration: have a point (a theme), a body of knowledge, and actively explore that theme in front of your audience.

You too should be able to learn something from your talk. So take this as an opportunity to think on your feet.

This makes your speech exciting and entertaining, even if it also gives it a big probability of failure.

You may have to speak with notes when you are a beginner. Notes are a sort of safety net: If you use them, the probability to fail is minimal.

But you'll never do anything spectacular if you always rely on them. Spectacular means being willing to take risks.