A mentor of mine, wrote a book a while ago, and developed a method called VCC: Voice-Inflection Conviction Close. He taught it to use before the prospects came pouring into the show.
Voice inflection, the tone of your voice as well as the volume, greatly impacts your message. One technique is to control your pitch up and down and really animate the way you speak. This makes what you are saying easier to understand and more enjoyable to hear. I have been criticized for speaking in monotone a few times. This is a common tendency of people who are deep thinkers. This rule makes sense, as I would rather hear someone who is animated than speaking in a monotone if they are trying to sell me something.
Conviction, the emotion you put behind your words, is more important than your message. He told me that once, he deliberately renamed the topic of his speech to Elmer Fudd, when he was trying to sell a charity—something along the lines of The Elmer Fudd Charity, which was originally supposed to be the XYZ Charity. He talked on and on for about an hour about this charity with the funny name. No one laughed; because of the conviction behind his words, he was able to convince them to donate a record amount.
Remember to close the deal by asking for the sale.