Simplicity is key here, with the use of pictures or drawings to illustrate your points. This may be the most important part of a presentation. You may have to alter the sequence of data to suit your purposes. Authors often publish data which do not fit well with the issues you wish to discuss. Don't be reluctant to eliminate such data.
Organization generally leads to clarity.
An introduction is given which will lead the audience to the current topic. The length of the introduction depends upon the complexity of the subject. A few general slides are usually shown at this time. This part of the presentation should not exceed 5 minutes. After the topic is introduced, the speaker now frames the questions to be answered during the talk.