Delivery is the best-researched subject of the three. There are countless books, blogs and workshops. However, you have to really distinguish between 20th century public speaking and 21st century public speaking here. Most of the resources still focus on making you look confident when you don't quite feel confident. I am much more interested in playing with one's nervousness the way Woody Allen does it. To me, nervousness is not the problem—lying is.
I have read dozens of books on public speaking. Confessions of a Public Speaker by Scott Berkun is at the top of my list. It has a five-star rating on Amazon and deservedly so. It is written in an extremely accessible conversational style. It is full of industry insights and great stories. What's even more important, this book is very true to its title; it is in fact a confessional book. If you want to read a book on public speaking, this is the one.
Here's a relatively random quote from it:
The easiest way to be interesting is to be honest. … If you're honest, even if people disagree, they will find you interesting and keep listening.
And this is what the book is all about. It is about daring to say the truth to the microphone and the many details you need to be aware of in the process. It was a great inspiration for me when I was writing this book. It is so good that it's the only resource I mention here.
Among other things, Scott Berkun recommends taking a theater improv class for those willing ...