Preparation is essential if you want to be a good speaker.
There is an old public speaking story, attributed to different people, that essentially goes something like this: If I am to speak ten minutes, I need a week for preparation; if fifteen minutes, three days; if half an hour, two days; if an hour, I am ready now.
Humorous, yes, but there is a lot of truth in there as well. In my post on the social contract, I wrote about the need for speakers to add value for their audiences. They need to think long and hard about their key messages. They need to ask themselves why their audiences should care. They need to prepare.
And preparation takes work. If you have ever seen a great speech or presentation, you can be sure that however long the delivery was, significantly more time was spent preparing. A great speech is like an iceberg: what the audience sees is only the tip; what the audience does not see is the effort that went into the preparation.
Good public speaking takes effort and commitment and time. If you do not put in the time beforehand, you risk a substandard performance and the disappointment (or worse) of your audience. If you fail to prepare, be prepared to fail.