Fear of public speaking is right up there with a fear of heights. A whole lot of people don't relish the chance at speaking in front of a large crowd. Even giving a presentation in front of a relatively small group can be a harrowing experience---especially if it's a very important presentation: something that will lead to funding, a job, or promotion.
Stage fright can be debilitating. Your heart races, you pour with sweat, and your thoughts become muddled with anxiety. It can make public speaking absolutely impossible. There are pharmaceutical drugs available, but if you don't want to go that route, there are natural ways to tackle stage fright as well.
Stage fright occurs from a mixture of adrenaline and testosterone---the fight or flight mechanism going overboard. Simple relaxation techniques, such as visualizing a calm place while taking deep breaths, can be effective. You should also visualize success. Part of the tension associated with stage fright is thinking, over and over again, I'm going to fail, I'm going to make a fool out of myself. Visualizing that you will succeed is effective: the power of positive thinking.
Giving a Successful Presentation
Just because you're not nervous does not mean you will give a successful presentation. There is a lot more that goes into a good presentation than overcoming stage fright. Preparation is key, as is practice. Actually, they go hand in hand. The more prepared you are, the more confident you will be, and the more this will curb your nervousness.
Think of a presentation like a spoken essay. In a successful essay, the writer will begin with a topic sentence---outlining the theme for the entire essay. Each paragraph will have a specific focus, using examples to prove the thesis. A presentation needs to be this clear---it needs a focused outline in which each presentation point builds on the one before it.
It is recommended that you have a dress rehearsal of the presentation beforehand---ideally to colleagues who understand the subject. They may have suggestions about how you can improve the presentation, by elucidating on certain topics, using more visual examples, or rewriting certain elements.
Enunciation and pronunciation are also extremely important. You could have drafted a very concise and well-conceived presentation, but it all comes down to, well, the presentation. If you don't speak clearly, the meaning of your message will be lost. Practicing the presentation beforehand will ensure that you don't miss important cues.
In some sense, giving a presentation is something like being an actor---a tough ride for someone who's never acted a day in his or her life. Putting emphasis on different words in a sentence can drastically alter the sentences meaning and importance. Practicing a presentation beforehand will help ensure that you get the most of every sentence in the presentation.