When the restaurant or bar or shop or Department of Motor Vehicles closes, the doors click shut, lock, deny access. Yet even though operations have ceased, patrons might reflect on the atmosphere of the place, on the food or drink or merchandise or good prices they discovered and enjoyed; they might even, if luck was with them, walk out of the Department of Motor Vehicles with gratitude in their hearts because lines were short, employees friendly, and the photo on the new driver's license acceptable.
When you close a presentation, your aim is similar. Yes, your presentation ends, applause, applause, people file out and are soon on their way to the next thing. But you want them to take something away with them; you want them to reflect on your words, to recall and consider your perspective, your message.
Closing your presentation with care and grace can provide your audience a takeaway that serves as a reminder, an echo, a telescopic lens through which they can continue to reflect upon your words, your perspective, your message.
SIGNAL THAT THE END IS NEAR
Let listeners know that you are approaching the end of your presentation—use indicators to alert them, to stir their attention and sharpen their focus. While they may have an inkling that you are nearing your conclusion based upon the time the presentation was projected to last, use transitions or signal words to affirm their perception. These words can be as simple as "ultimately" or "meanwhile." They can be more complex, a sentence linking to something you said as you opened your presentation: "But let me return to the scenario I described earlier."
But also change your delivery. Alter your voice—pause a little more often, slow your pace, emphasize key words. Increase your eye focus. Change your stance. Use facial expressions that align your words and meaning. Although you will have been varying your delivery throughout your presentation, take special care with it as you near the closing so that your audience can take the same special care with its attention.
TIE THE ENDING TO THE BEGINNING AND THROUGH THE MIDDLE
Think of the end and the beginning of your presentation as a rope through which you loop the middle and then knot the three parts together. If you began with a story, for example, return to it at the presentation's end—elaborate on it, alter it, set it in the future—changing its characters or plot or some other detail that reinforces your message and establishes a lucid takeaway.
Or modify the occasion for which something you quoted originally occurred; speculate on how that quotation would be worded under the circumstances you created—circumstances that you addressed or described in the body of your talk. Predict, forecast, ask a question or answer a previous one. Enumerate the benefits or disadvantages of a belief, an achievement, a possible outcome. Recommend a course of action, its significance and advantages.
Importantly, populate the closing with the most evocative language you can craft. Create images, metaphors, similes, or analogies that capture and depict what you most want listeners to remember. Such figurative language tends to stay longer in the mind than ordinary, everyday language. It's dramatic, it appeals to the senses, it stirs associations and emotions.