Sleep gives your body a rest and allows it to prepare for the next day. It's like giving your body a mini-vacation. Sleep also gives your brain a chance to sort things out. Scientists aren't exactly sure what kinds of organizing your brain does while you sleep, but they think that sleep might be the time when the brain sorts and stores information, replaces chemicals, and solves problems.
Trouble sleeping is often a symptom of another disease or condition, such as depression, chronic pain, medications, or stress, which might explain why it’s so common. Longitudinal course and impact of insomnia symptoms in adolescents with and without chronic pain. Palermo TM, Law E, Churchill SS. The journal of pain : official journal of the American Pain Society, 2012, Sep.;13(11):1528-8447.

Innovative fibers like Celliant may help you drift off sooner. Used in Amerisleep mattress covers, Celliant is a fabric infused with minerals that absorbs body heat and converts it to infrared waves. It’s been shown to help regulate body temperature (to avoid overheating) and to boost circulation. In one study, people fell asleep 15 minutes faster on a mattress with a Celliant cover.

Benzodiazepines are the oldest class of sleep medications still commonly in use. Benzodiazepines as a group are thought to have a higher risk of dependence than other insomnia sedative hypnotics and are classified as controlled substances. Primarily used to treat anxiety disorders, benzodiazepines that have been approved to treat insomnia include estazolam (brand name ProSom), flurazepam (Dalmane), quazepam (Doral), temazepam (Restoril), and triazolam (Halcion).
For years sleep researchers have known that alcohol is the number one sleep aid in the world. If you look back at the results of the 2005 Sleep in America poll, you will find that 11 percent of those polled used alcohol as a sleep aid at least a few nights a week.  Another study conducted in the Detroit area showed that 13 percent of those polled had used alcohol as a sleep aid in the past year. However, the reality is alcohol is not the answer to getting better sleep. While alcohol can make you sleepy, it also does the following to detract from sound sleep:
How melatonin helps sleep: Melatonin can shorten the time it takes to fall asleep and increase overall sleep amounts, according to research. It’s been shown to improve quality of sleep and reduce daytime sleepiness and fatigue. Studies also show melatonin may increase REM sleep. It’s during REM sleep that we consolidate and process memory, and prime the regions of the brain associated with learning.

Unwind by keeping the lights low. Light signals the brain that it's time to wake up. Staying away from bright lights (including computer screens!), as well as meditating or listening to soothing music, can help your body relax. Try to avoid TV, computers and other electronics, and using your phone (including texting) at least 1 hour before you go to bed.

Uncomfortable bedding has been linked to poorer sleep quality, while a comfortable mattress can up the chances of a satisfying snooze—we swear by our Casper mattress. Effect of prescribed sleep surfaces on back pain and sleep quality in patients diagnosed with low back and shoulder pain. Jacobson BH, Boolani A, Dunklee G. Applied ergonomics, 2010, Jun.;42(1):1872-9126.
Apparently it's all to do with sleep cycles rather than getting more hours of sleep. If you wake up at the wrong time during a sleep cycle, you'll find yourself more tired - even if you were asleep for longer. So if, for example, you need to be awake by 6am, you should either get your head down at 8.46pm, 10.16pm or even 11.46pm or - if you're feeling like a real night owl - 1.16am.
Time to bust some long-held myths: Waking up early does not make you a better person. The early bird does not always catch the worm. Your circadian rhythm is your internal body clock, and it’s going to look different to your neighbor’s. When you go to sleep and wake up in accordance with your body’s natural circadian rhythm, you’ll sleep better, and be more alert and productive during the day. Dr. Michael Breus, a clinical psychologist and sleep expert, identified four sleep chronotypes (aka your circadian rhythm personality). These are:
The following steps are organized to provide you guidance and support in your efforts to sleep better. It can be implemented over the course of a month, with different tasks assigned to each of the 30 days. Major changes are spaced out in the schedule to allow prior tasks the time needed to take effect. Most of the first week, for example, focuses on improving your sleep environment after the recommendation to fix your waking time is in place—but some of the groundwork laid through self-reflection this week will provide a foundation later on. Similarly, as is later recommended, creating a relaxing buffer zone and going to bed when you feel sleepy will take some effort, while simultaneously rearranging the use of substances may come easier.
Experts say that during the teen years, the body's  rhythm (sort of like an internal biological clock) is temporarily reset, telling a person to fall asleep later and wake up later. This change might be due to the fact that the brain hormone   is produced later at night for teens than it is for kids and adults. This can make it harder for teens to fall asleep early.
Use a blue light filter on your device. The blue light emitted by smartphones and tablets can be a powerful sleep disruptor. It suppresses your body’s production of melatonin and throws your circadian rhythm off, making it harder to fall and stay asleep. Luckily, many smartphones these days have a “night shift” feature that adjusts the screen from cool (blue) to warm (yellow) light, which is less likely to keep you up past your bedtime. Likewise, there are apps you can run on your laptop or tablet that reduce blue light. Some popular ones are f.lux and Twilight.