The first shoulder stretch, the windmill stretch, is referenced
in many sources. However, many do not show the proper range of
motion for the stretch. To maximize its effectiveness, you want to
be sure to follow the diagrams carefully.
Now do the same rotation with your right arm. After
you are comfortable with this stretch, try doing both arms at the
same time. Each arm should be 180 degrees apart from the other.
Therefore, when one arm is above the head, the other arm will be
below the waist.
The final evolution of this stretch, is to practice it while
walking instead of standing still.