You may sound normal to yourself but to others your voice may be too high-pitched, your eyebrows furrowed or your face set unintentionally in a grimace. Be aware of behavior that may distract your audience. Practise in front of a mirror to get your presentation spot on. Listen to your voice, watch your gestures and revise accordingly. Videotape yourself so that you can evaluate your presentation.
People pick up on nervousness, defensiveness, insincerity, arrogance and lack of conviction.
Think the opposite of these and send positive signals. The listener must believe that you are sincere. You want to come across as an Individual with his own reasons for what he says. Yes, company lines must be toed but try not to sound like the trained corporate parrot. Use your own experiences to illustrate your points.