successful public speaking

How can a discussion of success?
In my class in public speaking, there is an assignment to discuss a topic (unchosenyet) four people, two in a group. I wonder how strong affctive work on it. Thank you.
It always seems like he is right, always reherse and try all the facts this discussion. Maintaining a strong face and narrow ridge, which helps you look smart. And finally, maintain confidence and keep in their right mind, even if you put a good argument
Successful public speaking : Body Language in Public Speaking