In order to make a successful presentation it is important to understand its purpose. Basically, the presentation "promotes" the paper (or book, or article) and is thus aimed at convincing the audience to read it. Thus, the information should be provided in brief form in order to cause in the audience a natural curiosity and interest, i.e. it is unreasonable to overload any of the sections with information, the volume of all structural components of the presentation should be proportionate to their importance, the "Results" section should be the longest one.
In addition, larger fonts are desirable in presentations (24 pt or larger). The use of full sentences is not mandatory in the PowerPoint version, as the author is supposed to remember the text of the presentation almost by heart.
As for the presentation design, it is highly desirable to use "readable" fonts like Times New roman, Verdana or Helvetica. The text should not be highlighted, whereas the author might wish to color the background and use animation. In this sense, it is important to make reasonable decisions concerning color, and to remember that the use of pictures is not mandatory, except diagrams or other visual support, which will become a bonus consequently, as tables are too difficult to human perception.
In order to provide more visual support, the author might write handout pages, which would contain a briefer version of the presentation. For handouts, PowerPoint format is not always appropriate, as smaller fonts can be used.
Before writing the presentation, the author should evaluate the audience and adjust the paper to their own purposes ad interests. For instance, experts and scientists do not need explanations and clarifications concerning the organizational aspects of the study, but they are likely to pay greater attention to statistical data and practical recommendations. Undergraduates and poorly competent viewers often need more information about the background of the problem, so it is acceptable to expand this section if they are majority in the audience.
Further information on Presentation Writing: