Get plenty of rest each night.
Sleep is essential. You should never sacrifice sleep, no matter what. Unless you are the kind of person who can survive on shorter amounts of sleep, you should be aiming for 7-8 hours of sleep a night. Not getting quality sleep will cause your brain to operate more slowly throughout the day, and you will not be able to focus on work and other responsibilities.
Sleep deprivation also increases stress. Want to live stress-free? Go to bed on time.
