If you are in sales, or you are pitching for investment, you might end up giving that presentation a 1,000 times. Do not say that to your audience, they hear it for the first time. Do not skip over points that seem obvious to you, they are not to the audience. And finally, do not leave that enthusiasm that you had the first time you gave the presentation.
Think of that musician that managed to inspire you with that song that she played for the 1,000th time. In short, give the 1,000th presentation as if it were your first.