Trainers in industry as well as courses in public speaking maintain a few rules that are essential to any type of speaking engagement:

Tell them what you are going to tell them.

Tell them what you want to tell them.

Tell them what you told them.

This is prudent advice based on research, regardless of the topic or audience.

Each lesson should have an identifiable introduction, a body and a summary of the information presented in the lecture. These three components fulfill different purposes in the learning process.