I do my best to avoid taking over-the-counter drugs, and have never had to really use a prescription for something like that. However, that does not mean that I did not have trouble sleeping myself. I would remember how easy it would be for me to pull all-nighters simply because of the difficulty I had in catching some shut-eye. I can only speak for myself as to what works for me, but if you haven't done these things, I think it's worth looking into.
First off, the biggest reason why I could not sleep (and why I think a lot of people have trouble sleeping) is because of the sedentary lifestyle I had as an adolescent. I don't think I have to explain much on this. When you lead an active lifestyle and devote a small portion of your day towards cardiovascular endurance training, you will more than likely get a better night's sleep. You'll also be a little more healthier overall, both in mind and body!
Next, and this ties in a little with the first one, is nutrition. Consuming large amounts of sugar, simple carbohydrates, or alcohol before bed is guaranteed to fuck with your sleep. Always opt for a more whole meal dinner and lay off the desserts or evening snacks. It is my view that we have a sugar problem in this country, and popping some night-night pills is only a band-aid solution to ONE of the many conditions it brings.
Lastly, I have found that using natural lighting, like a candle, combined with reading a book can help tremendously if you are really trying to force yourself to sleep. Puts me out like a light. Get it?
I hope you consider these good habits, because they certainly helped me in getting the sleep that I need to take on the day with a bright smile on my face! :)