When you are responsible for running an event, you need to get the timing right otherwise mayhem and disappointment will set in.

Always aim to get to the venue before the registrants / attendees - that way you can make sure there are no last minute hiccups and everything is ready to go.

Speak to the event staff before the day to ensure they know what is expected of them and whether you will need to modify your own timings (unlikely as they've probably done a million events by now).

If you have speakers, panels, sound guys etc etc - make sure they know the timings and running of the event as well. Advise the speakers (actually they should know this well in advance so they can prepare their presentation and / or speeches) of the time they have been allotted and whether that includes question time.

If you are the person who will be introducing the speakers make sure you have a biography for each speaker. If you haven't done this very often, read each bio out loud so you can practice the words in a real time environment. You would be surprised at how long it takes to read something out loud. Similarly if you are preparing a speech yourself, you will also want to practice this by saying it out loud. This gives you a feel for how right or wrong your timings are.

If you are feeding the attendees during the event, please bear in mind there will be periods of noise and disturbances and this should be taken into consideration.