I'll do the best I can,
Deep, restful sleep is the goal, not just unconsciousness. This is the problem most people think of with sleep apnea. They sleep, but wake up tired. They never gain enough
deep sleep. But, they also don't become awake enough to be aware that they are not "sleeping"!
Stimulants interfere with the deepest sleep: REM sleep. That's the part of sleep where you become more rested. (Also when you dream) In essence, think of the mind as (slightly) awake even if the body is asleep.
The sleep routine is about training your body to sleep. Get your mind to quiet down and let the deep sleep come. In a perfect world, a sleep routine would have you begin "getting ready to sleep" 30 minutes to 2 hours before you actually hit the pillow. Use that time to systematically:
1) Clear up the trials and tribulations of the day. Allow your mind to relax. Meditate.
2) Gain a comfortable environment. Reserving the bedroom for sleep alone will help que your body that it is time to sleep. Cool and dark are also signals that your body uses to know when to sleep. Don't let the room get too warm. Even if you pile on the blankets, a cool room helps. Some people recommend taking a hot shower before bed. It feels good, it's relaxing, plus your body is cooling off as you drift off to sleep.
3) Get your body ready to sleep. Clean up, Stretch out, get your body comfortable and relaxed...
Perhaps sleep isn't the problem. Do you get REM sleep? Do you wake up tired? Do you dream? (I think you mentioned you had a sleep study). That's a different can of worms...
Sleep is not very well understood. It's very individualized. It's really hard to apply good science to it. Unfortunately it is often becomes a detective case...
The Mayo center has a good website about sleep.
http://www.mayoclinic.com/health/sleep/SL99999
I hope this helps