You need to establish a warm and friendly relationship with your audience.
Enthusiasm is contagious. If you are enthusiastic the audience will be enthusiastic too.
Don’t forget to have eye contact with everybody in the audience. The eye contact must be natural – you are not allowed to stare at anybody so they will feel uncomfortable. A good eye contact will make everybody feel included in the group. A good eye contact will also make you aware of signs of boredom and disagreement.