Jeremy Donovan's study of TED talks suggests you engage your audience when you form a "chain" of questions:
- Ask a question and answer it in a way that creates a new question.
- Answer that question and answer it in a way that creates a new question
- Continue until the end of your presentation when you answer all your questions
Tim Wilson
Professional Speech Coach
Free speaking tips at: http://speakingquicktips.blogspot.com