Although speaking in public is really a monologue of sorts, this monologue is addressed to a ready, able and receptive audience who wants to learn from you as much as you want to learn from them.
Speaking in public would be more effective if it is listened to. The following are effective tips to maintain that necessary contact with the audience.
Minutes before your actual speaking engagement, you could walk around the venue and familiarize yourself with the people who will be listening to you. As the people and the attendees arrive, give them a warm greeting. It is so much easier to deliver a speech to a group of people whom you consider as friends than to a bunch of anonymous faces.
Honestly, people expect and want you to succeed. Audiences want to be as informed, stimulated and entertained as they could be. If you fail, they cringe with you. Succeed and your audience benefits just as well from your great speaking performance.
There is nothing to be sorry about
If you mention to the audience that you are nervous or if you express your apologies to any problems you think may exist about your speech or your speech delivery, you may be setting them up to focus on that thing you are apologizing for. You do not have to mention this to them, chances are they haven't noticed this until you brought it up. Relax and be silent. Your audience will relax with you.
Establish eye contact
Connect with your audience, appear natural. Or better yet, be as natural as you can be, without overdoing it of course. You should be able to get the audience to nod their heads as an acknowledgement of what you are trying to convey. Do not breeze through your speech. Pause for a while or for a brief moment, especially at those points you want to emphasize. This is also a good time to establish eye contact with your attendees as well as to catch that much needed breath.
Do not debate
If during the question and answer part of your speaking engagement an audience expresses disagreement with any part of your message, you need not aggressively prove your point to him or her. A debate is not just a futile means to get your point across but it could just as well never be resolved. Get that attendee to talk with you after your speaking engagement, never during.