Sleep is essential for recovery, growth, information retention, attention span, healthy weight, and too many other benefits to list. The issue with getting enough sleep, which is 7-9 hours for adults according to recent data, is actually falling asleep fast. 
If you allot eight hours for sleep and you cannot fall asleep for two hours, you will be under the sleep amount required for optimal function. This can really screw up your performance the next day and beyond!
So how do you fall asleep fast?
It is all about setting up a routine and an environment conducive to falling into that deep slumber.
Tips to Help Fall Asleep Fast
1) The Bedroom Is for Two Things, Sleeping and Having Sex
I learned this my freshman year of university in Psych 101. It stuck like body paint to a nipple. Since that day, I have not had a television in my room. Unless reading a good book to relax before bed, I do nothing in my bedroom outside of sex and sleep.
Even your smartphone, do not use it in your bedroom! More on this later.
Just get in bed. If with your partner, have sex then go to sleep. If alone - Well, never mind. The bottom line is your brain will associate the bedroom with sleeping and the horizontal mambo. If you're not fornicating, only one thing to do... Sleep!
Note. It is 100% okay to have sex in places other than your bedroom. I just recommend not falling asleep afterwards if in public.
2) Shut Down Your Smartphone 20 Minutes Pre-Bedtime
This one will hurt some millennials, and prevents that epic pre-bed selfie of your fine rear-end, but you'll thank me when you fall asleep fast.
Artificial light - up to an hour before bed - can suppress melatonin and make you more alert.  If you're like me an hour is a bit much, so let's turn that off for 20 minutes. However, if you look at point one and need your phone to watch porn to enhance the act I guess we can make an exception.
How to make a 30 second high protein brownie.
When I am not traveling, my wife and I make an MTS Whey brownie, brew a cup of decaf coffee, and go down in the basement and watch TV for 20-30 minutes. We then come upstairs, brush our teeth, and go to sleep (or do that other thing you do in the bedroom).
We are programmed to do this, and I try to keep a similar routine even when traveling in hotels. Form your own bedtime habit to program sleep into your mind. The power of habit is immense.
4) Dark and Cold
Be sure to make your room as dark as possible, with dark shades and blinds. Keep the temperature between 60 and 67 degrees Fahrenheit. 
If you're like me, you care about your electric bill too much to do this. Get a fan or install a ceiling fan and keep the air at 72 degrees or so. This should suffice and not speed global warming too much.
If all of this isn't enough, a good sleep supplement containing melatonin will help. Melatonin is a potent antioxidant, anti-inflammatory, and immune system booster, and controls circadian rhythms that are responsible for your body getting into "sleep mode."
The best bet is to get a complete formula that addresses stress, inflammation, falling to sleep, staying asleep and hitting REM (the most important phase of sleep) and waking up refreshed. For this, I recommend my MTS Nutrition Machine Sleep Aid - the most complete formula on the market.
This will help a lot, but try the other methods first and see if they do the trick!
Sleep to Live
There you have it! Try all or some of these strategies and enjoy falling asleep fast. Your quality of life depends on it.