How to Create a Successful Tech Event
blog.evenues.com
blog.evenues.com
Have two AV inputs, one for the live presenter, and one 'standby' that's just hooked up to a monitor right next to the podium or something, and some kind of easy way to switch them over. That way while Presenter 1 is going, Presenter two can plug in / set resolution / restart a laptop 3 times, etc. If any presenter is playing a video, make sure the sound works and reaches to the back of the room.
I've been to two (otherwise great) 'A big batch of startups get two minutes each to pitch' events in the past month where we've burned half an hour of awkward DJ time in between the 'quickfire' presentations because presenters were getting the projector to play nice, which would've been avoided easily if they'd have done a dry-run the night before. I know these are tough and usually using borrowed resources, but why risk ruining your event to save a few hours of work in the week before the event?