Get some ZZZZZZs

Did you know that your body burns calories while you are asleep? Getting a good night's rest, maybe 6-8 hours, does your body good. World class body builders and professional fitness competitors make it a rule to get in at least 8 hours of sleep to get themselves in top competition form.
After a day of working at the office, and then working out at the gym, your body needs rest so that it may perform its own "self-recovery". Your body has the ability to heal itself while you are asleep. Muscles that are sore after working out have to be repaired so that they become stronger. This is all done while you are sleeping.
So make sure that you are getting the proper rest so that you can maintain your workouts to the best of your abilities.