Good sleep habits include:
Minimize caffeine intake and avoid both caffeine and alcohol 4-5 hours before bedtime.
Avoid intense exercise 4–5 hours before your desired bedtime.
Avoid large meals and large quantities of liquid before bedtime.
Follow a regular sleep/wake schedule each day even on weekends and during vacations.
Avoid shift-work.
If unable to fall asleep, go to another room and start a quiet and not too engaging activity. Return to bed only when you feel sleepy.
Minimize light in your bedroom from windows, alarm clocks, night lights, TV, laptops, tables, cell phones, etc. If electronics are needed, use blue-light screen filters (blue light is BAD!)
Minimize sound in your bedroom from pets, music, and other disturbances. Use earplugs or white noise like a fan or air filter if sound cannot be minimized.
Maintain a moderate temperature and good ventilation in your bedroom.
Do not work or watch TV in your bedroom. Use the bed only for sleep and physical romance.
If you have trouble breathing through your nose or snore, address common allergies (dust, mold, pets), and use nasal strips or nasal dilators to help you breathe. Air filters may be helpful.
If you suspect obstructive sleep apnea (stopping breathing during sleep when the tongue slips back blocking your throat), have a sleep study done and use the CPAP machine nightly if it is prescribed.
If you have trouble falling asleep, consider trying an warm Epsom salt bath or melatonin (0.5–5.0 mg) 30–60 minutes before bedtime. If you have trouble staying asleep, consider trying a time-release form of melatonin. Oral magnesium (100–300 mg of a chelated form) may also be helpful.
If you frequently become wide awake in the middle of the night, consider a small snack with protein and fat before bed. If that does not help, consider a trial of phosphatidylserine 500–1000 mg an hour before bed to reduce night time cortisol spikes.
You will recover more quickly if you structure your life so you can listen and attend to your body when your body tells you to rest.
Further reading: Matthew Walker, PhD's Why We Sleep