Stand with erect posture. Look out at your audience or straight ahead. Refrain from slumping. Good posture will help you to breathe more effectively.
Focus on your diaphragm. This is the area in the center of your body, just below your rib cage. Use the abdominal muscles in this area to support your tone as you speak. Relying on these muscles will allow you to speak with more power and to use your air more effectively.
Relax the major muscle groups of your body, especially in your face, neck and shoulders. As you focus on the various parts of your body, tense the muscles for a few seconds and then release them. This will help to reduce anxiety, which in turn makes it easier to breathe properly.
Visualize something or someone that calms you. Visualization can reduce your anxiety and help you breathe more slowly.
Allow yourself time to speak. Do not rush yourself, which can cause you to run out of breath. Enunciate and remind yourself that you are not in a hurry.