One way to ensure effective retention of the lecture content is to encourage participants to review it repeatedly. To keep repetition from becoming boring, subtly change the repeated review task to keep the participants engaged.
After the lecture, ask participants to identify the most important piece of information you presented. After a suitable pause, ask participants to share their decisions. Present another category (such as the most useful or most controversial) and ask participants to select an appropriate point from your presentation that satisfies the requested Superlative. After making the choice, ask participants ...