The Audience
You, as the presenter are the one side of the communication equation. The other one is the audience. In order to deliver an effective and eventually successful communication/presentation, it is of utmost importance to get to know the audience. Find out as much information as you can during the preparation phase of the presentation.
Information you need to find out from the organizer of the presentation or by researching yourself:
Handle the audience
The presentation is organized for the benefit of the audience and you as the presenter you should always have this in mind. Therefore, it is important to do whatever you can to add value to your presentation and enable the audience to make the most out of it. Opinions or facts stated in your presentation may initiate hostility or strongly opposing opinions. You should be prepared to cope with such situations by being a soother that an instigator of hostility and tension.
Do not interpret body language signs of the audience in isolation rather look at the whole picture. For example crossed legs by itself do not mean negativity.
Emphasize points of agreement with hecklers and repeat your opinion at the end.
Do not maintain prolonged eye contact with a hostile audience member, this may cause escalation.
Do not lose your temper under any circumstances.
Do not involve yourself in tension or hostility among audience members. Be the mediator, defuse tension and bring the presentation back on track.
Answer questions
Remember that a presentation is most often a two-way communication. You should structure your presentation in such a way to allow time, depending on the subject of the presentation, for questions from the audience. You should be prepared to answer to expected and unexpected questions.
