I conduct workshops in Communication and Public Speaking - we go into depth about internal components and external technique.
Ze Frank nails it in this short video. As always, he's straight up and quirky. His style probably doesn't appeal to some, although I can't imagine it.
This is the most important lesson about public speaking, or in fact, about life - that you have to be you. Emulation of others is a good start but ultimately, you have to let go and be yourself.
Jeff Adshead