At TEDxStuttgart, we do rehearsals with our speakers. Some of them are still surprised when we mention it - it's not something conferences usually do (maybe they should?).
Such a rehearsal is pretty simple and informal, actually: Two members of the team meet up with a speaker in their home, office, or a neutral place (we don't have offices ourselves and the venue is usually not available before the event). We set up a camera and let the speaker do his or her talk.
It's straightforward, as I said. The main reason for the recording is to give the other team members an idea of the talk. It does have a welcome side effect, though: It puts some pressure on the speaker. On more than one occasion, this turned out to be necessary; the speaker realised only then that this is serious and that we're not taking this whole TEDx thing lightly. Usually, our speakers are already well-prepared and we can only suggest a few minor improvements. There are, however, cases where the speaker only realises that he or she is not ready yet when we show up with the camera.
It's easy to fall into this trap. You know you are familiar with your topic. You have a basic outline for your talk. You go through it in your head: "First, I'm going to be talking about this. Then I'll mention that." And so on. But that's not rehearsing. By showing up with the camera, we force the speaker to give the talk, in one go, here and now. The camera is recording, time is running - they can't just stop and collect their thoughts or start over. They have to do it now.
As much as I (and pretty much every other speaker I know) hate it to watch recordings of myself, I can only recommend this approach. If you only do this for yourself, you don't have to show the recording to anyone else. Although that may actually help increase the pressure a little.
Personally, I like working with friendly audiences; friends or people who I know are interested in listening when I'm trying out a new presentation and will give me some honest, straightforward feedback. If you don't have anyone to turn to or if you don't feel ready just yet, recording yourself is a good first step. Once you have a recording that's not too bad, consider sending it to a friend for review.
Whichever way you choose: Please do rehearse your talk before you step out in front of your real audience. You would think that's standard practice by now, but judging from some talks I've seen (and still see), not every speaker does this, even though it would help them immensely.
(Photo: My rehearsal setup - my digital camera on a tripod, in a speaker's studio)
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