I kind of have this same problem, but it starts off on purpose, I go to bed and I start thinking about something on purpose but then I start to drift off to other topics and usually it takes me at least half an hour to fall asleep.

I highly agree with thenumbrrone, even on days I come home full of energy, if I take a hot shower late at night, I will sometimes start to drift off to sleep in the shower. So if its a day that I need to get to sleep early, I just go to bed right after and I will be asleep within 10 minutes.

I also find for me, that I can't fall asleep because of the heat. On days that its hot, I can go to bed tired, but the longer I think about stuff, the harder the heat makes it for me to fall asleep. Usually for this I get a glass of cold water it helps a bit.

I also do have a last resort tactic which is like a hardcore version of counting sheep. I close my eyes and put something over them like a sheet or my arm and I block out outside thought, I try my best to think just about the counting. If I feel myself slowing down the counting, I just force my attention back on it. I count from 1 to 100 quickly over and over, and sometimes I manages to fall asleep by the time I hit 1000.

I hope this can help.

There are two interesting sleeping things I've heard: 
One, teens get sleepy later than adults but they need two more hours of sleep.
Second, it's better to think of a waterfall than counting sheep, apparently it's more calming for your mind.

If you really aren't that tired at night, you could try to take a nap when you're home from school. It might not be as relaxing but it might be enough to get more energy.

I take an incredibly light dosage of a blood pressure medication and 10mg time released melatonin to get sleepy. When I do get sleepy, I still have trouble going to sleep. For that, I take 10mg instant release melatonin. Melatonin is a chemical that occurs naturally in the brain, so there's nothing harmful to be had from it.

I used to have this problem on the weekends when i was in the military. I found the exercising like thenumberone said helped a lot. There was a gym right next to my barracks in the CQ building, right about the laundry room, and I would just go up and there and tire myself out. 

But, since I have been out of the military, I just can't fall asleep until late, mostly because I had a job with night hours earlier this year, and still haven't had it corrected. Heck, even taking melatonin doesn't work. But, you could always try that. You can either get it in a prescription or over the counter. ( I was taking it in gummy form before I got a prescription ) 

thing1 :
thenumberone :
supernerd117 :

Thanks for your guy's advice. I'll try it out. It might just be heat, or weather change. But exercise definitely should help.

A user of this : I used to have this problem too. Breathing deeply while I was in bed helped me sleep. Me and my sister have an easier time sleeping when there's white noise. If you don't know what white noise is, it'd be something like a fan or the rain. Yoshi says he sleeps to this: http://thebest404pageever.com/swf/SREEP.swf
that might be something to try.

These are just a bunch of things that work for me, so it might not work for you.

I'm sure it's the computer.  You're hard wired to have everything instantly at your finger tips and when you don't get stimulation, your brain panics.  This could be the start of true internet addiction.

Try going without the computer, except for critical schoolwork, for four days.  You won't miss anything in reality but put it down.  Try reading, exercise, cleaning the house, everything else except the computer and video games.  When you stop having instant feedback and constant bombardment of stimulation, you'll start slowing down and being able to fall asleep.

Saying that, try keeping a pad of paper and a pencil next to your bed.  When you think of ideas, write them down so you can worry about them in the morning.  That will help you focus your mind.  Try sitting quietly with no stimulation for five minutes and practice not thinking about things.  It's called meditation and it can be a tremendous help to bring your active, busy mind down to nothingness.  It can quiet you and bring some inner peace so you can fall asleep.

Good luck.

Exercising has the opposite effect on me. I can go out and and workout for an hour and a half, come home physically tired and eat a bigass plate of pasta but not fall asleep for a while. That is because after you exercise, you have that sugar rush, even after an hour I still have that rush. HOWEVER that is just me, my gf falls asleep like a baby after a good session of cardio. If it works for you too then that is great but do not falter if it doesn't.

I get the same problem with insomnia but only at night. Maybe you are an owl and only sleeps during the day. Some people are like that and thus they work the graveyard shift. I usually stay up til after 2am, mostly around 3:30am is when I say hey it's bed time. Then I end up browsing for news on my phone for at least 30 minutes. It isn't so much insomnia but more of the fact that my body just don't want to or like to sleep at that time because my clock isn't wired like that anymore. Can I forcefully change it? You betcha. Do I want to? No. But let's say I need to sleep at 10pm. Assuming you do not have fatal familial insomnia, here are a few tips:

1. EAT. A LOT. LIKE A LOT. Gorge yourself and tell me you don't get tired. I don't suggest people to do this a lot because eating a lot right before bed isn't good for you but it works so well.
2. Take some diph (short fordiphenhydramine). It is the active ingredient in some sleeping pills. Hell just take any sleeping pill. As for diph, it is highly abused and I don't suggest you taking more than 1. If you take 3, you will start tripping. Do not get hooked on this drug, kids, you will end up in the ER because you will end up ODing. Use it only and ONLY for sleeping issues. Always follow the recommended dosage.
3. If you are old enough and have someone available who is willing, have sex. An orgasm or two can definitely make you tired. IF you are a lonely person, don't fret. Call yourself romeo and your hand juliet. Works just as well.
4. Find and smoke cannabidiol if you are over 18. If you are going to argue against this, go ahead but like my neighbor used to say, "If you are an atheist, go study religion before trying to argue with me."
5. Some people have a routine before they bed for the night. What is yours? Already have one but it is taking too much time? Shorten it. Some people read before bed. Some drink milk, brush their teeth, then say goodnight to all the pet hamsters.
6. Combo the attacks. You can do all #1 - #5. Or just two. Remember, when tuberculosis was first being treated with drugs, they found that one method was not enough, drugs A, B, and C were all needed to tackle said disease. Sometimes you have to hit your problems with as many solutions as possible to remedy it.

Good luck and have fun sleeping. No one should be deprived on sleep since it is so important that we need to spend 1/3 of our life doing it. If this persists I would go see a doctor. IF you have fatal familial insomnia (a super rare sleep disorder/disease), my heart goes out to you and I hope they find a cure within 3 months so they can save your life. I hope my post helps.

Dreaming on,
TitaniumOxide

TitaniumOxide :
You shoudlnt eat pasta before going to bed.
Its a great meal for energy, but if you are planning to go to sleep then its a poor choice.
It continues to release energy for a few hours.
Equally, if you go to sleep while its doing that, it turns to fat.
Infact a lot of people make the mistake of thinking pastas are healthy eating, but its only really good if you are getting regular exercise. Too much is pretty unhealthy.

Your tips:
1.I eat before bed, its like a 4th meal, and I dont know if thats the reason why sometimes I cant sleep, but its widely believed it does effect your sleep pattern. Many foods are definitively proven to prevent sleep, some are proven to aid it.
2.There are a tonne of things you can take, including natural herbal extracts. For some, it knocks them cold, for others it does nothing.
3.Not particularly great on a warm night, many people (myself included) have difficulty sleeping in the heat.
4.Not sure about that one, forgetting the legality, I wouldn't encourage using any drug regularly. I find alcohol helps me sleep (despite it being reported to do the opposite) but I wouldn't be prepared to drink every night. Also, falling asleep after lighting something up is in fact pretty dangerous. Weed doesn't tend to have chemicals to keep it burning so it would likely go out, but even still.
5.Routine is good. Whatever works for the individual. Reading is pretty good too, but the choice of book is pretty important. Anything too exciting can stop you putting the book down and over stimulate your brain.

And yeh, doctors can help. Although if this is America he is in (im assuming it is), that will cost money, and not everyone has it.

Supposedly, certain foods you eat on Thanksgiving contain chemicals that help you sleep easier.

I'm going to go the other way on this. Why sleep? I'm not saying just sit in front of the computer all night. What I am saying is when you think it's time to rest your body then do it. Lay in bed in the dark and just rest your body. Lay there for 6 hours awake if need be. Focusing on trying to sleep is frustrating and causes restlessness in bed. If you tell yourself that you're just there to lay still and give your body a break, there will be no pressure to achieve unconsciousness and perhaps it will happen if you're not thinking that it should happen.