I has been awhile since my 6th grade and up class did any drawing from life.  I decided to have them work on contour drawings of shoes.  We warmed up by doing blind contour drawings.  This is when you draw an object while looking at the object the whole time and never looking at your paper.  There was a lot of grumbling with this exercise, but I really could see that they were learning.  After we were warmed up, we drew the shoes again, this time with a modified contour.  They could look at their paper now and then, but their eyes should be on the object 70-80% of the time.  It really is a challenge to trust your eyes and draw what you see, not what you know is there.  I am very proud of this group.  I think they did an amazing job!