"There is no such animal, in or out of captivity, as a born public speaker," wrote Dale Carnegie in "The Quick & Easy Way to Effective Speaking."
Indeed, public speaking is an acquired art that is refined by practice and experience. Solid content, effective communication and self-confidence are the foundations of effective public speaking.

Content
First, find something you really want to talk about. You need to believe in your message before your audience can believe in it. That's why more than anything, you've got to have passion before you step up to the podium. Be enthusiastic and excited about sharing your ideas, thoughts and impressions with other people. There really aren't any strangers---we are all strung together on the thread of human experiences. Just everyday happenings, narrated with humor and insight, will help you to connect with your audience.
"When speakers have a real message in their head and heart---an inner urge to speak---they are almost sure to do themselves credit, Carnegie wrote in his book "Public Speaking for Success."

Confidence
Believe not just in your message but also in yourself. You're not the only speaker in history to have a butterfly garden in your stomach before a speech.
Toastmasters International offers some tips (see Reference). First, visualize yourself giving a successful speech. Imagine that you are standing in front of an appreciative audience, listening intently to your interesting talk, which you deliver with clarity and confidence. Visualize your audience applauding you--it will help instill self-confidence.

Communication
The success of your speech depends on effective communication. Establish eye contact with your audience. Adopt a relaxed stance and body language. Use everyday, conversational language. Avoid a stentorian tone and use words that most people are familiar with. For example, instead of "floccinaucinihilipilification," just say "worthless." Use anecdotes, personal stories, and humor. Even dry business charts can be enlivened with a personal touch.

Preparation
At first, practice your speech in front of a mirror. Look up the correct pronunciation of words that are not familiar to you. Practice voice modulation. Nobody wants to listen to a 45-minute speech on technology insertion, delivered in a monotone.
Toastmasters International suggests to familiarize yourself with the audience beforehand; greet and mingle with few people prior to the meeting. This way, you'll be more at ease when you stand at the podium and deliver your speech. Arrive early and do a dry run with the equipment--microphone, overhead projector and such.

Delivery
Your speech is like a cat. It has a head (introduction), body (middle) and tail (conclusion). Be mindful of the time and structure of your talk. Don't go overboard in one section and skate over others. Engage the audience in your talk. Tell stories that everyone can identify with. Pause after telling a joke. Remember, this is not high school---there are no bullies. Your audience wants you to succeed.