Plan content for 60% of your time slot
If you’re given a full hour, take no more than 40 minutes. That will leave time for Q&A, a panel, or some other form of discussion. It’s hard to keep people’s attention for much longer than 40 minutes, unless you’ve invited interesting guest speakers, inserted video clips, or utilized interactive exercises. As Thomas Jefferson put it, “Speeches that are measured by the hour will die with the hour.”
Trim your slide deck
If you created an hour-long presentation and want to deliver it in 40 minutes, cut your slides by a third. You can work in slide-sorter mode in PowerPoint. I make what I call a “slide cemetery” at the very end of the file and drag slides to that section when trimming. Don’t delete them, because you might have to resurrect one or more at the last minute, when you’re answering questions.