Only few people in the audience will notice anyway. Presentation Don't organize your talk in advance. It is usually best not to even think about it until your name has been announced by the session chair. Above all, don't write the talk out, for it may fall into enemy hands. Never, ever, rehearse, even briefly.
Talks are best when they arise spontaneously and in random order.
Leave it as an exercice for the listener to assemble your thoughts properly and make sense out of what you say. Discuss each slide in complete detail, especially those parts irrelevant to the main points of your talk. If you suspect that there is anyone in the audience who is not asleep, return to a previous slide and discuss it again. Face the projection screen, mumble, and talk as fast as possible, especially while making important points. Wave the light pointer around the room, or at least move the beam rapidly about the slide image in small circles.