What verbal and nonverbal characteristics can a speaker effectively use in a presentation?

A speaker should have voice projection and voice variation. Voice projection is just how loud you are, and voice variation is when you don't speak monotone. You want to have facial expressions and hand gestures. As well, avoid filler Words like "umm", "ahh", and other things like that. Try to have a good pace (not too fast or too slow) and ahow intrest. You may want to have audience participation, such as "raise your hand if you like ice cream" and then elaborate on these topics. Hope this helps!

P.S the best way to be good at something is to practice practice!