Generally, it is always easier to stay up an hour later than to go to sleep an hour earlier, so most people have relatively little problem setting the clocks back in the Fall. This is because our basic circadian rhythm (the "body clock") actually seems to be programmed for a longer than 24 hour day: it runs a little slow.
To sleep well, your body clock has to be in synch with your daily schedule. What sets your body clock is mostly your wakeup time. A consistent wake time is the single best measure you can take for good sleep habits. Bad sleepers are told that no matter how poor their night's sleep was, they should get up at the same time each morning. The main signal to your brain to wake up in the morning is light exposure. Natural daylight is best, but even artificial light will wake you up (and should be avoided as much as possible near bedtime). In general, the most you can easily shift your body clock is one hour a day (which is the reason for "jetlag" when changing time zones).
Ten rules for good sleep (getting your body clock to work for you)
1. Maintain a constant wake time. Vary no more than one hour a day, even on weekends.
2. Beds are for sleeping. Don't do anything requiring concentration in the bedroom. Read something light, perhaps. Even a TV in the bedroom is a bad idea for many people.
3. Bedtime = sleeptime. Spend only about as much time as you think you will sleep. For most people, 8 hours or less time in bed will lead to more solid periods of sleep.
4. Exercise is good for sleep, but not in the few hours before bedtime.
5. Don't go to bed right after a big meal, but don't go to bed hungry either.
6. Consider a "worry time" in the evening, at least an hour before bedtime, when you can write down everything you are worried about, or need to do the next day, and then put it aside and relax for the last hour before bedtime.
7. Caffeine is bad for both getting to sleep and staying asleep, and its effects can last for up to 12 hours. Avoid this for several hours before bedtime.
8. Alcohol may make it easier to fall asleep, but causes abnormal sleep, and often leads to awakenings as the effects wear off in a few hours. Avoid this before bedtime.
9. Exposure to light in the morning is good for waking you up. Natural light is best (go outside if the sun is up).
10. Finally, don't worry too much about your sleep. Everyone has occasional bad night, and the effects of a single bad night's sleep are not serious.
Prolonged mental fatigue can impair self-control and increase aggression