But feelings are what move people. When you need to sell an idea, a product, or yourself, emotion does the persuading. You can convey emotion by what you say, as well as by how you say it. Especially when much of what you must present is factual or statistical, it's good to begin with a personal anecdote or a dramatic story or a provocative question. Your listeners will be engaged immediately, and receptive to hearing the meat of your argument.
Analogy is also particularly valuable.
Everything you say will have more impact and make more sense if you vary the volume of your voice. Let the meaning of your words dictate when to increase the volume, and when to drop down to a softer level. Inflect your voice up on key words and phrases. A presentation delivered in monotone is monotonous. A presentation is also a visual experience.