Many people don't realize it, but public speaking is a skill like any other, and it can be trained. When organizations like Toastmasters International teach people public speaking, they usually focus on the following six categories:
Experienced and effective inspirational speakers tend to use a lot more hand gestures than those who are new to it. People who are learning to be better public speakers will be taught to use their arms and hands to emphasize certain points of their speech, thus giving their audience visual cues as well as purely auditory ones.
Changing inflection is key when it comes to keeping your audience interested in what you have to say. Beginners may tend to be too monotonous, and so public speaking training addresses this by explaining when and how to vary your inflection.
3. Vocabulary & word choice
The use of a large vocabulary can make a speech much more precise and interesting for the listeners. Keynote motivational speakers make good use of their vocabulary to make their speech effective. It also allows variation in key words used, so that a particular word or words is not repeated again and again, which is a distracting habit. The best way to improve your vocabulary is simply to read more, and to look up words you don't know.
4. Use of notes
Truly keynote motivational speakers don't use them at all, but for most of us notes are necessary to remind us of where we are in a speech and what is coming next. The key is to have notes that have the correct level of detail, and this usually means making them as succinct as possible. Ideally, speaking notes will serve only as a reminder of sections of a speech that are already more or less memorized by the speaker.
Effective use of humour lifts almost any speech, and for some public speaking, for example wedding speeches, it is positively expected. It can be hard to pull off though, and so public speaking training looks at when and how to deploy it.
6. Developing a rapport
Developing rapport with your audience basically entails getting (and keeping) them on your side. There are certain things a speaker can do to get an audience on-side (for example, presenting a sympathetic story, and certain things they can do that will kill rapport (for example, being patronizing), and public speaking training looks at these.