The United States' National Sleep Foundation gathered a large panel of experts and put them to work. This allowed them to publish a list of criteria that indicate that you had a good night's sleep: it took you less than 30 minutes to fall asleep, you didn't wake up more than once, and if you did wake up in the middle of the night, you didn't stay awake for more than 20 minutes, and you were in a deep sleep 85% of time you spent in bed.
Obviously, we don't sleep with a stopwatch under our pillows, but there are tools that allow us to measure the quality of our sleep, such as mobile applications like "Sleep Cycle" or "Sleep as Android", which are able to detect and analyze your sleep cycles.
Optimise your sleep
So let's say you have a way of measuring the quality of your sleep and want to sleep better: what should you do? For starters, focus on the quality of your biological clock by giving your brain clear cues, by going to bed and getting up at the same time as often as possible. You can mark these two moments with rituals, such as reading a book or massaging yourself before going to bed, for example.
Eating very light and earlier will make it a lot easier for you to sleep, and exercising in the daytime will help your body relax and use its resting mechanisms in the nighttime.
You may also want to consider airing the room before going to sleep to oxygenate it, and reduce screen time and exposure to light one hour before you go to bed. One last piece of advice would be to use your bed exclusively for sleep (no eating, watching series, reading messages or work) so that the brain can associate this space with rest.
What about waking up?
Now that you're getting a great night's sleep, you could go further by trying to help your body wake up optimally. First, the hardest rule is to force yourself to get up the first time your alarm rings and not use the "snooze" your alarm clock's snooze button. Several studies reveal that this behavior strongly affects your motivation for the day and makes it harder to wake up.
One trick you can use is moving your alarm clock away from the bed, to force yourself to step out from under your warm comforter. Once you're up, the first thing your body needs is a large glass of water, because the work it did to recover all night long left it dehydrated. Adding a little lemon to your water will also be good for your digestive system.
Afterwards, if you're up for it, you can try a ritual, such as practicing a few minutes of silence or meditation, so you can take your time waking up and not start off the day feeling stressed. You can also exercise or invigorate yourself by taking a nice, cold shower.