Apple - 20 Stroke Exercise - We did this exercise in Barbara Jaenicke's Class today. I've also seen Karen Margulis do this. It's harder than you think but a very beneficial exercise. You sketch a simple apple shape. Then choose several colors and paint in fewer than 20 strokes.
Landscape - 100 Stroke Exercise - This exercise was one of the most difficult. We had a simple reference photo. After sketching in the major shapes you paint in 100 or fewer strokes. The point is to make the most effective use of each stroke placement and to not "over work" the painting. Overworking the painting creates "mud". I'm pretty good at making mud. My goal is to daily paint several small paintings limiting my strokes until I feel more comfortable with lighter and fewer strokes. You do begin to see the color layers better.