The beginning of your main results should be smoothly entered, having prepared the audience adequately. Similarly, there should be a smooth transition, as you begin to present your conclusions. I shall use 4-7 minutes for evaluations by your fellow students, so you have the full M minutes to use. If you finish early and there are no questions, you must elicit some discussion from your audience. One way to do this is to ask them some questions, which you might have expected them to ask.
Prepared overheads are very effective visual aids when they are designed and used properly.
Blackboard writing is not suggested, except for answering a question, because it takes time and will not communicate as well as a carefully designed overhead. If you do, you are likely to run into trouble. Let the audience know right away if you welcome questions during the presentation, or whether you prefer that they wait until the end. If someone points out a mistake, thank them. Make each overhead clear and uncluttered .