craigb
I've been in front of large numbers of people before. The trick is to BE COMPLETELY PREPARED, then make sure you're relaxed (helps to take in deep breathes then let them out slowly). but what I found to be the most important is to enter the hall as if you own it and keep that attitude. Some (that you don't want help from) will try to assist, so you need to show you're in control and then everyone tends to settle down. However, if you looked panicked, lost or puzzled, you will lose the crowd and it's downhill from there!
Some good advice there. I actually find the presentations pretty easy - it's the damn logistics and expense (800 room nights at the hotel, feeding 400 over multiple days, buses to offsite events, etc.) that are a nightmare.
Prepping for the keynotes is a ton of work, but I actually enjoy the on-stage part. :)