10. Not knowing what’s coming next… or, failure to have done a practice run.
Like offence no. 1, both professors and amateurs can be guilty of this.
For the professor who commits this offence, I suspect it’s because you’ve had some underling put together the slide-deck. So you stand up full of confidence that you know all about the topic and assume you can speak to the presentation. But the thing is, if you haven’t looked at it before you get up, things are never in exactly the right order.
You’ll end up either flicking forward and back as you discover (on the spot) how you really want to tell the story or hit a speed bump every time you move to the next slide and wonder ‘What is this meant to contribute?’. Neither is at all conducive to a gripping presentation.
For the amateur who commits this offence, I suspect it’s because it just feels a bit weird to deliver the talk to yourself in the mirror. I promise you, if you are too scared to hear your own voice giving the presentation in an empty room, you will be terrified about opening your mouth in a room full of your contemporaries and role-models at a conference.
Rehearsing also helps you figure out the best moment to move from slide to slide and lodges it in your head so your nerves won’t get the better of you when you’re delivering it for real.
The bottom line is: respect the time your audience is putting in to coming, and make the most of having them there — ie. know what you want to say!