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.

This stretch should be done slowly. Stand straight up, with your hands at your sides.

Continue to raise the arm, but angle it toward your head. As you bring the arm back, try to brush your bicep against your face.

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.