The first element of body language to focus on is the use of posture. During your presentation you want to give an impression that you are not only confident and relaxed, but also dynamic.
To help you do this, it is a good idea to remember the following 3 points:
Face the whole audience as much as you can while you speak. Avoid the mistake of angling your body toward only one side of those watching you. Be especially careful not to show your back to look at any slides being used.
Keep a stable posture. A good way to maintain stability is to stand with your feet about 30 centimeters apart with one foot slightly in front of the other. Stability is increased even more if you bend your knees slightly.
Although you should be as stable as possible in your posture, don’t stay in the same position through your talk. Good presenters appear dynamic because they are not stuck behind a podium. They will move and walk toward the audience and also use both the left and right parts of the stage.