What's your most important tool of influence in speeches and presentations?

Let's dispense with some usual suspects that aren't even in the running: Your content. PowerPoint. A lectern or microphone. Your reputation, or fame. (Being charismatic does help. To learn more, download our free ebook, "12 Easy Ways to Achieve Presence and Charisma.")

You'll "get warmer" if you think in terms of you rather than anything external—for you yourself are the premier influencer in your presentations by far. What exactly accomplishes this influence? Is it your voice? Your gestures? How about the way you occupy space and relate to people and objects? Eye contact? Facial expressions? Your posture and the way you stand and move?

How to Enrich Your Presentations

You've probably guessed by now that all of those items in the last paragraph constitute body language. It's the element of your presentation that tells an audience what you intend, how you feel about your topic and them, what has meaning in the context of what you're saying, and how committed and passionate you are.

Yes, content matters. But it doesn't matter enough. Think of the presentations and speeches you've seen recently. Chances are the subject matter, and sometimes even the data, was known before the speaker began. But what about these questions: "Is this person credible on this topic?" "Can I trust him or her?" "Why does this matter to me and how and why should I use this information?" — These are some of the things each of us asks about presenters, and it's body language that's ideally suited to provide answers.

Body language, then, is a powerful communication tool. Yet because of its power, you as speaker can undermine your message and your own credibility by weak or inappropriate body language. Following, then, are 5 ways you can weaken what you're saying through ineffective use of this important public speaking tool. 

1. "Muddying" Your Entrance. The first part of your message has to do entirely with yourself, as you show your audience that you are the appropriate messenger to deliver it. You're about to give a performance, and you should allow the audience a moment of expectancy in preparing to receive it. Your body language, that is, should separate the "take a look at me and get ready," from "now I'm about to begin. (Once you do begin, be sure you grab your audience with one of the 12 foolproof ways to open a speech.)

Here's why this matters: No matter how fulsome an introduction you may have received, your audience isn't really there for you until you're standing in front of them, ready to start. Their thoughts are still with the person who introduced you, or the remark their friend sitting next to them just made. To be sure your listeners really are ready to listen to you, walk to your spot and look at the audience silently for a moment. Smile, nod. You'll feel the audience's attention gather up and deliver itself to you. Now start to speak.

Nervousness makes many a presenter begin speaking before they've arrived at the place they'll be speaking from, or starting before everyone is ready. One of the most powerful ways you can influence an audience is by grabbing their attention with the first thing you say. If they're not ready to hear it, you've just basically helped destroy your message.

 2. A Defensive or Uncertain Stance. Once in place, do you stand as though you're at ease in front of an audience (as you must be), or does your stance broadcast your self-consciousness? If you're unsure of what this means, think about the speakers you've seen who assume a weak or defensive stance: the hands in the "steeple" position or clasped tightly; the "hand-washer"; or the speaker who twirls his or her wedding ring, or other examples that seem to say, "I'm not comfortable up here." For a reminder, on the other hand, of how visual input impacts an audience's receptiveness, discover Bill Clinton's secret of success as a speaker.

Nothing is as common or as undermining in terms of stance as the fig leaf position. It could also be called the "I-don't-know-what-to-do-with-my-hands" position. It looks like this:

Mostly, speakers do something with their hands. Very few have the poise and courage to simply stand with hands at one's side—which is actually the neutral position from which gestures can arise quite naturally. Watch Amy Lockwood's TED Talk to see an extraordinary level of physical ease. 

Keeping your hands at your sides with this level of discipline guarantees that your audience will listen to what you're saying, rather than being distracted by what you're doing. If they are distracted in that way, then you've helped dilute their focus and in effect destroyed your impact. Practice instead being comfortable with this level of stillness to keep your critical message front and center.

3. Moving on Key Points. Did you know that movement can help your audience make sense of what you're saying and retain key points afterwards? Many speakers use movement (when they're not standing stock-still) that is random: either wandering aimlessly as they speak, or pacing back and forth tiger-like because of adrenaline and, presumably, the need to find a slow-moving gazelle before dinnertime.

Such movement lacks purpose. To move purposefully, on the other hand, means to tie your position on a stage or at one end of the room with the content of your talk. Let's say you have three main points: doesn't it make sense to deliver each of them in a different spot? It may only be a step or two, but it makes clear that you are about to discuss a different point. Or perhaps you're giving a chronological narrative; if so, you should move from the audience's left to their right, since we read from left to right, and we see a timeline that way as well.

Contrast this with what happens when you move while you're moving into a key point. The audience is distracted by your movement (see above), and they're probably paying more attention to that than your key point. Worse is something nervous speakers sometimes do: retreating as they're saying something important. Why back off an important idea as you're expressing it? Your listeners will be thoroughly confused. Once again, you'll have helped destroy your own key message. 

4. Lack of Vocal Expressiveness. There are many reasons people gather to hear a speaker rather than merely reading the content of a presentation. One of the most important has to do with voice. The human voice is an infinitely variable tool of communication, which means it is one of your most powerful body language tools. Your listeners are not only adept at grasping meaning through your vocal variety, they depend upon your skill with your voice to do so.

That's because information is never enough on its own. Facts, figures, charts and other raw information cannot transcend itself—it fulfills its job of providing data, but it can't do more than that. It is up to you as presenter to give your audience more: to place information in context, to flesh out, to explain, to give the significance of what is being shown, and to tell them why it should matter to them.

You need vocal expressiveness to do so. The voice is physical, which means it is an essential part of body language. Compare in your head the next monotonous speaker you hear with Martin Luther King, Jr., Shirley MacLaine, Barack Obama, or Ellen DeGeneres. If you're weak in this area, work with a tape recorder (or your smart phone) to improve, especially in terms of pitch variety and vocal color. To deprive your message of this vital element of communication is to undermine the importance of what you're saying. Click here for some more ways you can use the world's most powerful tool for persuading audiences. 

5. Inappropriate Gestures. Many problems in terms of weak gestures are caused by sheer nervousness. Your hand and arm movements should support or amplify what you're saying. Gestures that are overly repetitive, inappropriate, or simply odd will destroy your effectiveness in no time flat.

Do you rub your belly at random moments? Kick the podium? Slap your hand on the tabletop so that your most important points are drowned out? Point to questioners as if you're jabbing them in the chest? I've had clients or trainees that did every one of these things. And you can bet the people listening were instantly jolted out of the stream of attention they were floating along on! Hamlet told a visiting theatrical troupe to "Suit the action to the word, the word to the action." It's princely advice we all should follow.

Key takeaways from this blog:

• You are the most important tool of influence when you present.
• You can undermine your own message through weak body language.
• Set yourself and let your audience get ready before you speak.
• Take a strong stance, and move just before you make a key point.
• Vocal expressiveness gives audiences clues information can't provide.