Structure your viewgraphs in such a way that the images are able to convey most of the story by themselves, even if you are hard to understand. Posture and gestures. Stand straight up. Avoid distracting mannerisms like swinging the pointer aimlessly around. Speaking with a hand in your pocket looks sloppy and unattractive.
Gestures can underscore spoken language.
Genuine enthusiasm accounts for 90 percent of a speaker's success. The speaker should attempt to control the crowd, permitting question as the speaker's convenience. By making it politely clear that the audience should not interrupt, the speaker will discourage impulsive ad hoc questions and can focus on the presentations. In doing so, you will also establish control and authority. This is tricky than it seems since an inexperienced speaker may have omitted an essential piece of information the audience need to understand the talk.