Its never harder to stay tuned-in than when a presenter seems to be all over the place.
To keep this from being you: work on your craft by finding a common thread in your speech and follow it all the way through to the end.
Tie everything into that common thread and keep your audience on track with you without any surprises.
Have you ever been in the audience when the presenter ventured into what seemed to talk about everything except for his topic and when he does mention something that is in line with his topic you’re not sure where it fits? Then you know what your audience will feel if you are “that guy.”
This common thread that you identify and use throughout your presentation should add value to your overall topic.