When teaching a computer related course, for example MS Office, especially when I reach the intermediate level of Word, Excel or Powerpoint, I found that 15-20 min of lecture, including an instructor demo of the excercise (like working with textboxes, customizing charts, using powerpoint animation) followed by a period of individual student lab might not be most effective. The technicalities (what button to click...) might be too many for the students to follow in the individual part.
Many times I have used "Follow Me": I set the stage explaining with a schetch the desired outcome and the basic procedure, then… >>>