Observe a regular bedtime and awakening time.
Establishing a schedule for sleep is very important. The best way to do this is to establish a "bedtime," then allow yourself to sleep until you spontaneously awaken. Do this every night for a week or two (great thing to do during a vacation). This exercise will help you establish exactly how much sleep you need.
For the sake of discussion, let's say the average sleep time was 8 hours.
Now determine what time you need to wake up in the morning. Be sure to consider how much time you need to get yourself ready for work. Let's say this is 7 a.m.
Now calculate back eight hours from 7 a.m., meaning that 11 p.m. would be an appropriate bedtime for optimal sleep.