A presentation should have a clear purpose. Whether your purpose is to present a science project in the classroom or present a sales pitch to a new client. Decide whether you are informing your audience or trying to persuade them. Have key points that make your audience understand your purpose, and repeat them throughout.
For your presentation to be effective, it must engage your audience. Ask yourself who your audience is. Are they fellow classmates? Businesspeople? Club members? Determine the interests of your audience and tailor your presentation accordingly.
The introduction should capture the attention of the audience. Explain what you will be presenting, why it's important and establish credibility for yourself. You can establish credibility by explaining your experience in the field and the work you've done on the research and preparation of the presentation. Don't use jokes, apologies or questions as part of your introduction.
Visual aids can help engage the audience, but also ensure everyone is on the same page throughout the presentation. Use visual aids such as a PowerPoint presentation with photographs and charts or use a short video demonstration. Visual aids should be presented in direct correlation with your presentation and not lumped together at one time in the presentation.
Before presenting live, try practicing in front of family and friends or a video camera. Replay the video and watch it as if you were attending your presentation. Look for any awkward hand gestures, and judge whether your presentation makes sense to you. Ensure that there is no use of slang, or long pauses that make you appear unsure of your presentation.