It is often helpful to suggest to a witness that their task is similar to a teacher's. By conceptualizing their role as an educator a witness can take more control of their testimony. Many witnesses report that when jurors are not looking at them, they worry that their testimony is not being well-received. Teachers are familiar with such audience practices, and usually does not personalize them. Whenever possible, a witness should be assisted in characterizing their testimony using numerical references.
Numerical references invite jurors to take notes.
Of course, the attorney may not tell a witness what to say, but it is the attorney's role to help the witness learn to communicate effectively. Therefore, it is helpful to show a witness a specific portion of their videotaped testimony that was weak, and then immediately assist them to improve that segment. We learn better by observing our mistakes and practicing the correct response. However, merely pointing to a segment in the video tape and saying 'don't do that when you're really on the witness stand,' guarantees that the behavior will be repeated. Rather, take time to re-formulate the question and allow them to answer it again.