The key to a successful speech is story telling. The key to story telling is not to memorize the words, but to memorize the experience. As a trained stage and film actor, I do this using a technique called personalization. It means tapping into an experience from my life and applying the emotional impact of that experience to the story.
For example, when Anthony Hopkins is playing the role of serial killer
Hannibal Lecter in the film, Silence of the Lambs, he recreates the
emotional impact from an experience in his life where he was so mad that
he wanted to kill someone. What we see on the screen is Hopkins as a
psychopathic killer. In reality, Hopkins the actor is playing out the
emotional reality of his substituted experience.
One of my best-known signature stories is the Meatball Sandwich (see http://www.brodow.com/video.html). As I
describe each person's action in the story, I substitute my own behavior
from a similar experience. When I relate a character’s reaction to the
situation, it is me reacting. As a result, no one else can tell this
story the way I do. Each time I tell the story, it is different. But it
always grabs the audience because the emotions and behavior are alive
and in the moment.