The sound of your voice has got to be interesting, so change the pitch, use different tones, pause for effect... but mainly get out there and practice. How do you project your voice? Projecting is ...
If you get your posture right, this helps you to project your voice more effectively.
Good posture will help you to project your voice. Plant your feet shoulder width apart. Be aware of your body language. Use gesture to emphasise key points. Look confident and deliver with conviction.