1. Recognise that sleep is your friend.
Some people pride themselves on minimal sleep. For many of them, there will be a cost to health.
Your body cleans itself, restores hormone balance, improves the brain, and much more while you're sleeping!
2. Darkness
Allow no artificial light into your room. Remove all lights, LEDs get heavy blinds, etc. Start the darkness at least 30 minutes before bed and consider blue-blocking glasses for a few hours before sleep.
3. Have a consistent wake-up time.
Sleeping in on weekends or staying up late throws everything off.
When the goal is to improve health set the goal of getting up at the same time.
4. Go To Bed
By getting up at the same time you will become tired and that will allow you to get to sleep at a good time. Don't fight it staying up late and waking up with the alarm blaring while you're in a deep sleep.
A cool room, fresh air, magnesium, and other things can be added to this equation but if you're getting these big ones together with your training and diet you're well on your way to improved health.