"Our body language is our mother tongue and it tells about you and your interaction with others ." (Johan Borghäll, former lecture at SDU Odense, "Kropssproget" 2007)
Presenting an idea is an interaction with your customer or target group where both verbal and non-verbal languages is used to convince the buyers.
To convince someone you have to be trustworthy, likeble and even better sympathic.
Albert Mehrabian (1939 - ), currently Professor Emeritus of Psychology, UCLA, is worldwide known as the "7%-38%-55% Rule", for the relative impact of words, tone of voice, and body language when speaking. (video 1) The three elements account differently for our liking or trustworthy for the person who puts forward a message concerning.
So do you want to impact your customer or sell your idea? Improve your body language.
The best way to practice an improve your body language is doing drama exercises and role plays. Ex. act different emotions, imagine presenting in front of different target groups or focusing on different parts of your body and do experimental movements.
When you pitch or make a presentation of your idea.
Read more here
Read more in this book: Michael Weiss "Presentation Skills"