What are the three examples (ways) of higlighting key material within a speech?

Answer 1

Raise (or lower voice), gesture, or pause. Are the 3 most common ways. For variety, you can use a combination of any of the three.

Answer 2

Flat out saying "the key things to remember are...." or repetition throughout the speech, or using transitions "the first key point is", then later "besides the first point, another key point is..." and then later "just as important as X and Y is ...."