It's the old speaker litany about telling them what you're going to tell them, telling them, then telling them what you told them. Clayton recommends using a table of contents slide. As you start a new section, go back to it with the next subsection in boldface. Take a lesson from television commercials. They use visuals to supplement the message, not repeat it.
Audiences respond best to people.
If you're talking about building morale, supplement your words with pictures of smiling faces. Purely text-based visuals are about as effective as no visuals. If they come before the speech, people will read them instead of listening to you. Offer them afterward. Let those who are interested come get them at the end of the speech.