This is not one of those creepy "what does your body language say about you" pieces.
It's more about essential body language hacks so people listen to what you say when you are speaking to a group. Here it is in six.
Stand up straight is much more than just what your Mom told you. If you want to be listened to you make sure that you look like you are fully there and enjoying yourself. Posture is important even if you are speaking while sitting. Upright and perky in the chair is what you want.
2. Moving Around
These days people expect that anyone passionate about their subject will be moving around. People who are really on top of things will be walking, approaching the audience and performing in the space. I call it "using the room as their theater".
3. Hand Movements
These are known as gestures in drama, and are the hand movements that we make naturally when you are talking about something you care about. They add interest and energy and should be done fully. No half-gestures please. Practice now - how would you welcome a room full of people?
4. Head Movements
These next 3 are all about using your head. First one up is movement of your whole head.
This may be from up and down, turning one way or the other or any of the natural movements that good speakers make. Next time you are watching someone interesting being interviewed watch how much they move their heads.
5. Face Expressions
Happy, Sad, Worried, Excited. Since we were all little kids we have been recognizing how people are feeling through facial expressions. An animated face is just more interesting to look at. And it shows authenticity which is the watchword these days for any good communication.
6. Eye Contact
This should definitely not be last but one of them has to be. Eye contact with your audience is how you connect when you can't reach out and shake everyone's hand. Eye contact should be held for a second or two and you should cover everyone is a friendly sweep of the room.