Some people believe that public speaking is an ability that only a few "chosen ones" can execute well. While I personally don't consider myself to be a great public speaker, I do think that anyone can become one. While the ability of being charming, engaging and persuasive comes naturally to some people (think Steve Jobs), I strongly believe that these are traits that can be learned and, more importantly, perfected over time - case in point, Mark Zuckerberg. His first talks were, for a lack of a better term, utterly pathetic, and he seemed to be unprepared and very nervous all the time. Over time he became more confident and his last talks were just brilliant.
One of my favorite hobbies is watching talks or speeches of people that are extremely passionate about the topic that they are talking about, specially in the realm of technology. However, I have noticed that many of my collegues in software development lack one very important trait: Most of them, almost never use gestures.
As an italian descendant, and just like most italians and argentinians, I use gestures all the time when I speak, sometimes excessively (which is a bad thing), whether in public or in private. To me, gesturing is an extremely important tool, if not essential, when trying to convey a message to an audience - any audience - technical or not. You can think of it as a second language that augments and amplifies whatever it is that you're talking about, and in some cases, the only way to get the audience to really "understand" what you're talking about, or to get them to believe your message is by performing the proper gesture at the proper time. You probably know the idiom "a picture says more than a thousand words". Gestures work in the same way.
But you need to be careful, very careful, with the gestures you use. Just like with pictures, the wrong photo, or in this case, gesture, will invalidate whatever it is that you're saying. That's why psychologists and detectives look at gestures to detect when people are lying; While your mouth may be saying one thing, your body may be saying the opposite. If you happen to make that mistake your audience will notice. Trust me.
Over time, just for the sake of perfecting my talks, I've paid an absurd amount of time observing not great talks, but great speakers, and I've taken note of how they use gestures, and when. You'd be surprised to know that, without gestures, great talks become boring to look at.
Below you'll find a video of my favorite gestures and their meaning. Enjoy!