The conventional wisdom is that you should rehearse, rehearse and rehearse your presentation. I say: Not so fast! Be very careful that you do not over rehearse your presentation. Remember that your presentation is a conversation with your audience. If you come across as someone who is reciting a speech from memory, you lose that spontaneity and connection with your audience. Smooth is good. Too smooth is not so good. And slick is bad. It is not what you say; it is what your audience hears.
It goes without saying that you should know the topic of your presentation to the point where you do not need to refer to notes to speak. Once you master that, your “conversation” with your audience will be natural and spontaneous and your audience will sense it and accept you right away. It will connectwith you. Allow me to make a point: Let’s say someone gives you a set of PowerPoint slides with detail notes on Einstein’s Special Theory of Relativity. You rehearse it twenty times and now you can recite every word from the notes. Will you be comfortable to go out and present it to a group of theoretical physicists? I hope not.