There are literally hundreds of different scientific studies on the quantity and quality of sleep that people need to function well. But as a non-scientist like me looking for practical advice that I can apply to my own sleeping habits, it's hard to know who to believe. This study says one thing, while another study says something else.

But what if an expert were to sit down and look at all of the studies done and synthesize the essential findings and lessons from all of them, and then package them into a report that ordinary people like us could use to understand what truly makes for a good night's sleep?

That's exactly what Maurice Ohayon, the director of Stanford Sleep Epidemiology Research Center, did, according to a new article on the Science of Us blog. Ohayon and a team of sleep experts reviewed over 200 previously published sleep studies to identify the habits and behaviors of people who slept well.

In a new paper they published recently in Sleep Health, a journal published by the National Sleep Foundation, Ohayon and his team describe the four criteria they uncovered from sorting through hundreds of scientific studies on the subject. Here are four metrics they identified that indicate whether you've had a good night's sleep:

  1. You take half an hour or less to fall asleep.
  2. You wake up no more than once per night.
  3. If you do wake up in the middle of the night, you fall back asleep within 20 minutes.
  4. You're asleep for at least 85 percent of the time you spend in bed.

These metrics should give you a good set of benchmarks to determine whether you're likely to enjoy a good night's rest. But what should you do if you're having trouble falling asleep--and staying asleep?

The helpful folks at the Mayo Clinic have compiled a list of things you can do to prepare yourself for the kind of quality sleep that Ohayon and his colleagues identified in their study:

1. Stick to a sleep schedule.

The Mayo Clinic folks suggest that you go to bed and get up at the same time every day, even on weekends, holidays and days off. Consistency reinforces your body's sleep-wake cycle and helps promote better sleep at night, they say.

2. Watch what you eat or drink before going to bed.

Eating too much--or not enough--before falling asleep could lead to discomfort that keeps you awake. And, of course, steer clear of caffeinated drinks like coffee or tea. I try to not drink any coffee after about noontime, to make sure the effects wear off well before I'm supposed to tuck into bed. (My personal tip: Watch out for Wulong tea! Drinking too much of that has made it hard for me to fall asleep on several occasions.)

3. Create a bedtime ritual.

Take a shower, read a book, listen to music, or whatever helps you get into the frame of mind that says you're ready for bed, says Mayo. And limit your use of electronic devices like your laptop or smartphone (something I admit I have trouble keeping away from my bedside.)

4. Limit daytime naps.

Long naps during the day can interfere with nighttime sleep, warns Mayo. If you are going to nap, try to limit it to 10 to 30 minutes, and make it during the midafternoon, they suggest. I've found that napping during the day, which I do a few times a week, can interfere with my evening sleeping pattern, especially if I nap for more than 30 minutes.

Mayo has a few other useful pointers which you can find right here.