I doubt I'll be able to help much, because I have issues with sleep too. I've heard you're supposed to stay away from electronics for several hours before bed. Also avoid rigorous exercise? Try doing something relaxing before bed.

I find getting to sleep a major issue because:

a. I think sleep is a waste of time.

b. My brain is constantly at work

c. I want to read or write

d. I hate sleeping

e. I require little to no sleep to be alert and awake.

Try listening to music, or an audio book. 

Everyone's advice about avoiding electronics before bed is so true! Using electronics before sleep actually makes your brain more wide awake, making it harder to sleep. Instead, you can read a book or do something else besides using an electronic. Also, doing stretches before sleep calms you down. It's also hard to sleep if you're stressed out with something or really excited about something- both thoughts give you a jittery feeling. Try to keep your mind off of it. I also listen to soothing music while I sleep too. 

Try reading before bed as opposed to using the internet. Sometimes I just end up overcomplicating my thoughts while in bed and tire out my brain to force it to sleep. Or you could try focusing on your breathing and avoid thoughts altogether which seems to make me sleepy. Hope this helps!

First thing is to establish good sleep hygiene.

Exercising sometime during the day and eating well and regularly (but with the final meal of the day a few hours before bedtime) are important for maintaining regular and refreshing sleep.

Get off the electronics/anything that glows at least an hour before bed, or the light will mess around with your circadian cycle and if that happens you're gonna have a problem.

Try to go to bed at the same time every day, and once you're in bed, don't get up again. 

-> one possible way to do this: HabitRPG. Which is silly, but if you're into RPG stuff/respond well to rewards that are actually meaningless IRL? Setting a daily for going to bed and staying there at whatever your bedtime is will help a lot.  

Incorporating some kind of meditation into your bedtime routine might help if you're one of the racing thoughts people.

If you have a clock that's visible in the dark, or a watch that lights up/has luminous hands, cover it/take it off. Clockwatching will destroy your ability to sleep.

If you're a sleep is useless person, remind yourself frequently that sleep is important and you will die agonizingly without it. 

Destress as much as you can before bedtime (however you need to, meditation, quiet time, whatever as long as it's not super physically strenuous).

Trying to sleep if you're tired but not sleepy is a recipe for disaster—when you start getting sleepy, if it's close to bedtime, don't try to power through. Sleep. 

If the insomnia is a CHRONIC problem, sleep hygiene probably won't help much in the short term, but keep at it because it's good for you. ALSO:

Keep a sleep journal. Track when you go to bed and when you get up AS WELL AS when you went to sleep and when you woke up (i.e. how many hours you got), whether you woke up at all during the night, PLUS whether you woke up feeling refreshed (it is completely possible to get the recommended 9 hours of sleep but not feel it when you wake up because not all sleep is good sleep—another reason sleep hygeine is important. 

If you practice good sleep hygiene AND consistently take a long time to get to sleep, or wake up well before you get up, wake up frequently, or don't get good quality sleep for a period of more than a month, get yourself to a doctor because you might have a sleep disorder and those are heinous.

Aaaaaand if anyone tells you you're too young to have a sleep disorder: protip, they're wrong. Find someone who will treat you if you need it. I started developing DSPS when I was about ten/eleven and no one would believe me when I told them I couldn't sleep at night; it got progressively worse and eventually got mangled into ISWD which has turned out to be incredibly persistent—to the point that my doctor considers it a wild success if I get five consecutive hours of sleep in a night and then don't need any naps for the remainder of the day.

(...she says, writing at 2:40 in the morning)

POINT IS: Sleep is important. If you can't for a long time, get medical help.

Thanks for all the suggestions, everyone! Now you're making me sleepy! ;P

For some reason when I'm trying to go to sleep I imagine Harry Potter and other series spin-offs/fanfiction.  It helps!  I don't know why, but it does.

Before bed I read a chapter of a book. After that I fluff up my pillow, get into a comfortable position, and think nice thoughts closing my eyes.

I had trouble getting to sleep for awhile, so what I do is just clear my mind, and if I can't, think of calm things. Or I just pay attention to my breathing and I usually go to sleep pretty fast.

What my sister means is that our father reads aloud to us and our youngest sister at night. We sing a song, then tell about our day. After that, we pray and hit the sack. However, sometimes during the second story, Butterfly will conk out on the couch.

But, to get to the point, I used to take forever to sleep. I'd get into the bed at. . . oh nine at night, and get to sleep at ten or eleven. Often I'd wake at three or five o'clock. If I woke at five, I know that I could not get back to dreamland. That was a horrible phase. Now, I get to sleep MUCH faster, and only wake at night for about five minutes except for a nightmare. But I still wake up at six, and can't get to sleep in unfamiliar surroundings.

I'd say, just lie there, and wait. Close your eyes, lie still. Don't let yourself be distracted (If I can't get to sleep, that's because I am daydreaming about something.) and try not to get up. However, sometimes, water will help you. Turn the clock away, and just relax.