I sleep best if I follow all the standard "sleep hygiene" advice:
* no alcohol w/in a couple hours of bedtime
* no caffeine after noon
* no heavy exercise w/in a couple hours of bedtime
* cold bedroom
* quiet bedroom, or white noise
* pitch-black bedroom (tape over all those fucking LEDs)
* don't look at TV/computer/phone or sit in brightly lit room w/in an hour of bedtime