The eyes communicate powerful cognitive messages. Presenters should not underestimate their ability to persuade an audience with their eyes.
Eye contact is part of everyday communication and an audience can feel uncomfortable if they are denied it. Making eye contact with individuals gives them a sense of involvement in your presentation and helps to convey your objectives on a personal level. Make sure that you share eye contact with all members of a small audience and all areas of a large audience. Regularly shift your focus around the room, not so that you look nervous, but to help involve as many people as possible in your talk.