A few things that may or may not help and may or may not be applicable:
1. Don't worry about it. Worrying that you're not falling asleep is a great way to make it even harder to fall asleep. The worst that's going to happen in the short term is that you're going to feel a bit crap the next day from not getting enough sleep (and yes, I know there are more serious health results of chronic, severe sleep deprivation, but my point is it's not ebola). Not getting disproportionately worried is also a great way to avoid disproportionate responses, like getting yourself heavy sedatives that can cause more trouble in the long term.
2. Try to have a regular time at which you go to bed, and at which you get up. Yes, I know that's not always completely possible, but the more consistently you can do it, the more you train your body that certain times are for sleep, and other times aren't.
3. Don't use your bed for anything other than sleep (and sex). NO PHONES, COMPUTERS, SCREENS, ETC. IN BED!!! The extra light suppresses your sleep hormones, and the extra stimulation makes it harder for your brain/mind to settle down. Using your bed only for sleep also helps condition your body to gradually learn that BED = SLEEP.
4. Exercise early in the day. Exercise helps fatigue you, and generally promotes a neurochemical and hormonal balance conducive to good sleeping patterns. However, exercising too late in the day might make it hard to fall asleep.
5. Alcohol is bad for sleep. Yes, it might help you get to sleep, but the quality of the sleep will be poor, and you may have rebound effects that make it harder to sleep later on (or the next night).
6. Light and dark signal your body's sleep cycle. The less bright lighting you use in the evening, and the more bright light you get during the day, the better chance you will have of re-setting a consistent sleep cycle.
7. I've heard that reading in the evening is good for tiring out your brain, and that TV/computer is bad for it, but I don't know.
Whatever strategies you adopt, it can take a long time (months or years) to reset a good sleep pattern, but most people can eventually do it (I've certainly got a lot better over the last few years). Many of the available chemical shortcuts can cause dependence (i.e. you eventually start to need them always to get to sleep), tolerance (i.e. they eventually stop working), and generally make the situation worse in the long run if you use them too often (though occasional use when you REALLY need them is probably OK).
