They do this by starting at the top of the scene. Their energy level is strong when they begin. If it takes a speaker half an hour to warm up, he or she will likely lose the audience. This doesn't mean that you should open your speech by screaming or by jumping up and down. Ovson opens up with a story.
Great actors are great reactors.
They keep their senses open and alert, not anticipating what the other actor is going to do. Jack Nicholson's performances are more exciting because his response to the other actors' behavior is spontaneous and unplanned. Be there fully. Allow your senses to be aware of everything that is going on as you speak and adjust your presentation accordingly. Often my best material comes from what is happening in that meeting.