Would you deem it appropriate for Obama to give his State of the Union address while sitting in a “chris-cross-applesauce” position? No, you would not. That is because you know that he would look childish, immature, unprofessional, and similar to how I sat in elementary school. Body language dictates how we are perceived in any situation. On a very base, subconscious level, and this goes double when we’re in front of an audience, body language can make or break what people think of us and what we are saying in a matter of seconds. When all eyes are on you, your movements, posture and body language carry more gravity than usual, so each requires even more attention on your part.
Most studies find that verbal communication makes up less than 10 percent of all human communication, while nonverbal communication (i.e. body language, eye contact, etc.) makes up roughly 55 percent of communications. Here are a few tips to guarantee your body is portraying the message that aligns with your professional presentation.
Face your audience head on
Take a power stance: Square your shoulders to the direction of the audience and plant your feet far enough apart to be sturdy and balanced. However, if you’ve ample space when presenting, utilize it. Facing your audience head on doesn’t mean becoming a statue. Make it a deliberate point to move from point to point while you speak. This will give you a more vibrant, commanding presence that will demand attention from your audience.

Eye contact
Eye contact is a pivotal part of communication in Western culture. The unspoken understanding is that when a person avoids eye contact, it’s because they’re lying or nervous. When presenting, eye contact is vital in order to ensure your audience trusts the validity of what you’re saying.
A good trick is to pick out three people in the audience: one in the center of the audience, one in the left corner, and one in the right corner; Alternate between them.
Some will tell you all you need to do is pick a few spots on the back wall of the room, but the problem here is that you’re not actually connecting with anyone, and that can make the presentation feel insincere or inhuman. Eye contact is vital for making a connection with your audience.
Never underestimate the importance of good posture

An upright, open posture can signify success, confidence, honesty, positivity, vibrancy—the list is practically endless. The point is: have good posture. If you often catch yourself slouching, try standing and walking as if you were wearing a cape; that’ll give you a good idea of how you should be standing.
Posture is especially important when presenting, because it’s directly correlated to being perceived as confident. Your audience doesn’t want to listen to someone who doesn’t appear to be resolute in the message he or she is presenting.
While having a well-designed PowerPoint presentation from a PowerPoint specialist can go a long way in creating a clear, convincing professional presentation, there’s no substitute for confidence. Body language can reveal a lot about a person, and when correctly mastered, can do a great deal to ensure a lasting impression on others. The most important thing is to relax, remain open, and be comfortable in your own skin.