Don't tamper with smoke detectors or fire-alarm horns. They are there for your safety and could save your life. Check your smoke detector occasionally, and notify your RA immediately if it's not working. Keep stairwells and hallways free from obstructions. Don't prop fire doors open-closed, they help control the spread of smoke and fire.
Fire extinguishers work only if they are properly charged.
Don't allow anyone to play with an extinguisher.