Wendy and Stephen will listen more closely if they suddenly hear you mention their names. Name different kinds of people. When you're using people's names, don't name just men, or only women, Caucasians, African Americans or higher management. You get the idea. Your use of names should reflect the diversity of your audience.
Good speakers pepper their presentations with provocative questions.
Whenever you ask for volunteers, audiences perk up. If, for example, you are demonstrating how a digital whiteboard works, instead of writing on the board yourself, ask someone from the audience to do it while you describe the product's marvelous features. Whatever you do, don't leave them standing awkwardly onstage wondering what to do next. When they are finished, let them know. Provide opportunities for audience participation .