You're not going to go far as an entrepreneur if you're unable to string together a couple sentences and speak them aloud in the presence of others.
A blog I don't usually read called Art of Manliness recently had a lengthy post about one aspect of public speaking, namely, eradicating your "uh's" and "um's." These are "filler" words, which can mean you're stalling, be it thinking of the right word (meaning you have a large vocabulary and are flipping through it) or you actually don't know what to say at all. The point is, your audience won't know the difference because they aren't in your head. And as AoM says, "People will form judgments about your education, intelligence, background, and personality simply based on the sound of your voice and the language you use to express yourself."
It's the reason why Stephen Colbert saw fit to decimate his South Carolina accent -- he didn't want people to make assumptions about him based on the sound of his voice.
You don't have to go that far. AoM suggests, as does Toastmasters International, that you extensively prepare. Even better, if you can weave whatever you're saying into a story, you'll know where the beginning, middle and end are, so there's no need to stall or think deeply about what comes next.
Toastmasters adds an encouraging point for people who are terrified of public speaking: "Realize that people want you to succeed. Audiences want you to be interesting, stimulating, informative and entertaining. They're rooting for you."
See? They're rooting for you. Don't worry so much.
Read both posts linked here for way, way, way more tips. And whatever you do, just don't imagine anyone in their underwear. That's just distracting.
David Wolinsky is a freelance writer and a lifelong Chicagoan. In addition to currently serving as an interviewer-writer for Adult Swim, he's also a columnist for EGM. He was the Chicago city editor for The Onion A.V. Club where he provided in-depth daily coverage of this city's bustling arts/entertainment scene for half a decade. When not playing video games for work he's thinking of dashing out to Chicago Diner, Pizano's, or Yummy Yummy. His first career aspirations were to be a game-show host.