4.4 Perform physical housekeeping
This is another category where a little common sense can carry you a long way. Any computer will work best in a pristine environment that is temperature/humidity controlled and free of dust. Alas not many networks can afford such an environment, so an administrator must make the best of the environment he has.
Pay attention to ambient factors such as the heat; never put the server against ductwork, next to the air conditioner, and so on. Be wary of items that can cause interference with electrical pull (motors, microwaves, and the like) or EMI (electromagnetic interference), and try to utilize only isolated grounding circuits.
Keep the area around the server as free of debris and clutter ...