Before I begin a lecture/discussion, I begin a general discussion that incorporates the subject that I am about to begin, the students do not realize that I am gauging what they know about the subject before hand. I let them explain how they think that a certain process is done letting all the students add ideas as to how this process is done. I ask critical questions as the discussion progresses to make sure that they are incorporating all essential elements that must be considered. This peaks their interest so that when I start the lecture they can recognize if their thinking was on the right track!