Years ago I received two of the best instructional tips to use during a lecture: modulate your voice and move your face. I've found I can keep students attentive during lecture by changing the volume of my voice from loud down to a whisper and back to loud. In addition, I use exaggerated facial expressions as I speak. Students effectively stay focused on my face and concentrate on what I'm saying. I combine these two actions with moving around the room and direct Q&A with students during a lecture. Students stay focused, actively participate, and ultimately retain the material.