Lara Hogan’s Demystifying Public Speaking has been available as a physical book, and you can now read it for free online. I’ve done plenty of presentations in front of people, and after reading through this book, I realize what an amateur I’ve been.
This book is chock full of steps and ideas on not only creating your best presentation, but delivering it in a way that is interesting and, more importantly, worth the audience’s time.
The book is a little long and in depth for younger audiences, but the information inside could be summarized and delivered to them in a different form. As for high school students, they would find it invaluable preparing their presentations for classes or other events.