Not every C-level executive is a good public speaker. To speak authoritatively in front of groups, vary your speaking style and message to suit your audience. For example, if you are speaking to an in-house group, you can be more revealing about what's going on inside the company than if you are speaking to a group of reporters. Think Ronald Reagan when you want to inspire, Bill Clinton when you want to win someone over, Martin Luther King when you want to call to action, Vince Lombardi when you want to challenge, and Abraham Lincoln when you want to reflect your humanity. You can pick and choose bits of each person's style but be yourself. Your style emerges from who you are, your personal integrity, or to put another way, your authenticity. And the more often you speak in public, the better you will be.

Read more about public speaking:
- read the article at CIO