Check that the refrigerator is situated on an even surface. Move the fridge to another location, if the floor is wavy or has a significant amount of "give" or "play."
Place a level on the top of the refrigerator. Position the level to run from left to right across the front edge of the fridge.
Raise or lower the adjustable legs on the front of the refrigerator until the level shows the fridge is sitting evenly. Rotate the adjustable legs to the right to raise the refrigerator or to the left to lower it. Use a wooden block to hold up the front of the fridge if necessary.
Turn the level so that it lies across the top-center of the refrigerator from front-to-back. Check if the refrigerator is level on this plane as well. Raise or lower the adjustable legs as necessary, being careful to not upset the levelness of the fridge from left-to-right as you work.
Open the fridge door halfway once the refrigerator is leveled. Check that the door closes gently from this position, which is entirely normal. If the door slams closed or flings open, check the evenness of the fridge once more and make any necessary adjustments.