I stay up very late and sleep very late every day, and I get thrown off course by this. The scientific term for this is Delayed Sleep Phase Syndrome. It's caused by the Pineal gland and the circadian rhythm being out of sync with the sun. This happens to me especially in the summer, and so I want to work on this a little before school starts, so I'm already on a good schedule.
One suggestion that I've heard before is to get light first thing in the day. I have gotten away from that, but I have a special blue light I can use for that, and I've started to use it again when I first wake. It helps me wake up, as does looking at the computer screen. Getting out and into the sun is great of course, but especially in the fall and winter if you wake up early and go outside there's no sun to greet you, so the light comes in handy. So light helps cause wakefulness, especially blue, white and green light. The navy has found that very dim green lights in submarines increase wakefulness among submariners. After I read this I realized I have a glowing green alarm clock and wondered if this had any effect.
The sun, TV, Computer screen are all blue light and trigger wakefulness, so I may make it worse by surfing the net all night. It seems as if light at night, especially blue, white or green light make it harder for the body to produce melatonin, which causes sleepiness. Artificial light is unnatural and may disrupt sleep patterns in susceptible people.
One of the suggestions I read was to make your bedroom as dark as possible when you sleep. So I got curtains for my bedroom door and window, and put the AC in my bedroom instead so it would be cooler in the bedroom at night, and also since I'm blocking my bedroom off from the dining room at night with the curtain.
I also read a blog entry by a lady who had an interesting idea. She decided to use only candlelight for a few hours before bed. This is because red light may cause sleepiness. Red light apparently has the opposite effect of blue/green/white light. I know that red light doesn't affect night vision, so I wonder if it actually makes you sleepy or just doesn't have the bad effects that blue/green/white light does. I'm going to try this, and sit in my bedroom with candlelight an hour before I go to bed.