7. Talk slowly and clearly at the audience.

Everyone at Demo Day could see the difference between the people who'd been out in the world for a while and had presented to groups, and those who hadn't.

You need to use a completely different voice and manner talking to a roomful of people than you would in conversation. Everyday life gives you no practice in this. If you can't already do it, the best solution is to treat it as a consciously artificial trick, like juggling.

However, that doesn't mean you should talk like some kind of announcer. Audiences tune that out. What you need to do is talk in this artificial way, and yet make it seem conversational. (Writing is the same. Good writing is an elaborate effort to seem spontaneous.)

If you want to write out your whole presentation beforehand and memorize it, that's ok. That has worked for some groups in the past. But make sure to write something that sounds like spontaneous, informal speech, and deliver it that way too.

Err on the side of speaking slowly. At Demo Day, one of the founders mentioned a rule actors use: if you feel you're speaking too slowly, you're speaking at about the right speed.