Locate the spring-loaded hinge access plates at the bottom of the door at its pivot point. Remove the retaining screws from the plates with a Phillip screwdriver. Remove the plates from the door and place them aside.
Locate the adjustment screw at the end of the large spring mounted in the hinge assembly.
Twist the adjustment screw in a counterclockwise direction one full turn to lessen the spring tension on the door. Turn the screw in a clockwise direction to increase the spring tension.
Test the operation of the door by opening it fully and then releasing it. Note that the door should fully close on its own.
Turn the adjustment screw as needed until the door has just enough tension to close on its own without swinging too quickly or with too much force.
Replace the access plates at the bottom of the door and tighten the retaining screws with a Phillips screwdriver.