The outline and parts of your speech

Why do we need to create an outline?

First of all, it helps your creativity, because seeing things come together as a whole makes you want to add things or change them (or change their order). Secondly, it is obvious that creating an outline gets your thoughts organized. What you thought of before as single ideas will now get developed or perhaps dropped altogether, particularly when they do not seem to fit into the general pattern. Thirdly, an outline helps you state your main points clearly. Moreover, when you are ready to present your speech, a quick glance at your outline will help you remember the most important points.
Remember that writing an outline is a work in progress! Do not be afraid to add or delete things when you see that they do not fit into the overall plan. Very often you may need to rewrite your outline several times, as you add facts to the original “skeleton”.
What is described by Mr. J.H. Jowett above is the natural division of any speech or piece of writing for that matter. We tend to expect a speech to have an introduction, a main body and a conclusion. When listening to people, we notice (subconsciously or not) if the speech lacks a proper introduction, or if it ends abruptly, without any conclusion. Therefore, it is very important to pay attention to all three parts of a presentation.