"The mediocre teacher tells. The good teacher explains. The superior teacher demonstrates. The great teacher inspires."
~ William Arthur Ward (1921-1994)
Teachers should avoid clutter- keep the audience in mind. The audience is nobody else but your students. the class is about them and only them. No artist would dare place all of his painting's elements on one side of the painting and hence no teacher shoukd prepare a lesson thinking only about curricullum without analyzing the needs of the students, be it IQ or EQ.
Balance the contents so that the audience has a feeling of interest; just imagine yourself as being one of them. Would you really come to see yourself teach.... . Build up different parts of the class set, and when students moves to a different 'level' of interest or boredom, you will have the right move in your set ready to tackle them. If done subtly and prepared to the best of one's ability, the audience would not notice the shift, class will go on, they and you will enjoy it and you might just be the one that inspires others through teaching.
