4 Ways to Close Sales with Non-Verbal Communication Body language and facial expressions can be the ultimate negotiating weapons.

When you're practicing a sales pitch, you likely drill down on specific language. There's much to say about your product or service's value proposition, its competitive price and why your ideal customer needs to purchase it. But many are surprised to learn that, according to the research in the esteemed book Silent Messages by Albert Mehrabian, 55 percent of communication is non-verbal. Which means that your body language says more than your words -- by a long shot. Another 38 percent of communication comes down to tone, which leaves a slim 7 percent for the substance of the words themselves.

"Your words matter, of course," shares James Bell, CEO of James S Bell P.C. "But the knowledge of what your body language is conveying presents an enormous opportunity. If you can apply body language secrets to your next in-person pitch or meeting, you can boost your negotiating power and be at a considerable advantage."

And this advantage helps both in reading receptiveness to your pitch and coming across as more confident. Here are four ways to do so.

1. Evaluate body positioning.

Consultant Peter Stark has outlined how evaluating the way your counterpart sits is key in deciphering their level of interest. When someone is interested in what you have to say, they naturally lean in or move closer to you. And if they're closed off, the opposite is true: They'll position their body away from yours or move further back in their chair.

If you notice that the other person is leaning away, pivot directions in your pitch or ask them questions to understand where their disinterest may be stemming from. And, in the same vein, use your own body to lean forward and show your interest in having them as a client or as a partner.

2. Apply mimicry to make the other person feel safe.

Mimicry happens naturally when two people have been in close proximity for a while, but becoming conscious of it is a great idea in syncing up with another person. Tanya Chartrand, a marketing professor at Duke University, has written extensively about her belief that engaging in mimicry with another person can boost someone's sense that the other is persuasive and honest. So, if the person you're speaking to takes a pause before speaking, imitate the same. If they frequently pick up their pen, frequently pick up your own. This will make them feel safer with you subconsciously. All of this is very subtle.

3. Smile with genuine joy … when it's appropriate to do so.

Smiles have magical capabilities. They're truly contagious and can actually make people trust you more. Negotiation researchers Jeroen Stouten and David De Cremer created an experience in which they asked participants to evaluate the trustworthiness of their opponent, based solely on a picture. If the picture showed the opponent looking genuinely happy, the participants overwhelmingly voted in favor of their trustworthiness.

So, smile with genuine joy whenever it's appropriate to do so during your negotiation interaction, even if it's just when you first shake your counterpart's hand. Appropriate timing is fundamental. Peter Carnevale, professor at the University of Southern California's Marshall School of Business, has noted that an ill-timed smile can actually make you seem less cooperative. A prime example of ill-timing is right when negotiation is closing up and numbers have been decided upon. A smile, in this case, could indicate that you walked away from the negotiation with more than you'd initially bargained for.

4. Appear confident and relaxed.

Negotiating with someone who appears to be nervous and insecure can easily give you the upper hand. So, make sure that you walk into any negotiation with your shoulders back. Andres Lares, a managing partner for corporate consultants Shapiro Negotiations, has written about how the larger you can make your body presence with posture and a wide stance, the more authoritative and confident you look. This authoritative air grants greater credibility to your words, because it will be perceived that you have confidence in what you're saying.

Appearing to be relaxed goes hand in hand with appearing confident. Make sure not to fidget or do anything to indicate that you're antsy, such as shaking your leg or frequently touching your face. Firmly planting your feet on the ground is a great way to establish this presence, even if you're sitting down. Remind yourself mentally every few minutes to pull your shoulders back.

Not only will these non-verbal communication techniques boost your negotiating power, but they'll also have you feeling more confident. A great idea to make sure they're ready to go for your next negotiation or sales meeting is to try them out in conversations with friends, or watch how you communicate with your body by filming yourself giving a pitch in the comfort of your own office. The more often you instate these non-verbal cues, the more they'll become second nature, securing your negotiating power permanently.