Tip 12: Practice a shorter version. If you have 15 minutes to pitch, practice delivering it in 12 minutes.
Why? In front of a live audience, you will inevitably ad lib more content – even if you have very carefully practiced. You will change your content to a live audience. You will react to puzzled expressions by providing a little clarification or repetition. You will probably be tempted to try to turn the scowl into a nod. And when you are hit with a question mid-flow, you will need a bit of time to get yourself back into your pitch.
That is all OK. No-one can resist it, and in fact responding to your audience is critical. (It is why we require pitches to be in-person, rather than virtual, where it’s harder to respond to non-verbal communication).
But, if your practiced version is right on 15 minutes, your live version is now violating tip 10. So over-deliver in practice so that you can deliver on the day.