Go to bed at the first hint of being sleepy. At first, if that's 8:00 PM, just go to bed and be done with it - the important thing is to get normal sleep rhythms - you can work on syncing them with activities and clocks later. After many stressful years as a startup CTO/CEO, I had trouble sleeping. I'm under more stress now, but sleep pretty well almost all the time. The one thing I've learned is that if I ignore that first tired/sleepy signal, there's a good chance I've missed the boat and will not be able to get to sleep later. Staying up past 11:30 these days is a sure recipe for a bad night's sleep.

A "normal" night's sleep such as I experience now: At first sign of sleepiness, STOP whatever I'm doing and immediately get undressed and ready for bed. Brushing teeth is good dentally, but tends to wake me a bit, so I sometimes jsut swish with a hydrogen peroxide rinse and turn in. Turn out all lights and make sure room is dark. If not too tired, take melatonin and magnesium (I prefer magnesium taurate) - both promote sleep and relaxation. A year ago, I also started taking a limited part of my supplement regimen aimed at tissue repair overnight just before bedtime. It's working so well that I now think it does more good than everything else I take in the daytime (aimed more at energy production and utilization). If you're taking an autophagy and vitamin C regimen, this is the time to do it. Avoid B vitamins, as they're too energy-releasing.

Go to bed, head hits the pillow, say prayers (the mantra-like rosary seems to help my Catholic friends, mine are more stream-of-consciousness, but including a lot of deliberate thankfulness) and usually go to sleep in the process. If not, concentrate on the darkness, and if you're really stuck, find two background sounds to concentrate on at the same time - this almost always brings sleep.

I sometimes wake up in the middle of the night - if so, pee and maybe have a small drink of room-temp filtered water (cold water from the icebox is surprisingly good for waking - almost as good as coffee!), then immediately back to bed, where sleep usually comes easily.

Wake up to either sun, alarm, or sometimes, just your body waking up. I don't fight this anymore, either, esp. since I'm often going to bed by 11 at the latest. If I wake up at 5 AM, or even 3:30 or 4 AM, fine, get up and read/pray/plan. Often, especially in the middle of the night, this leads to sleepiness again - and I find that the "second sleep" that follows this is often the most refreshing. (N.B.: Set your phone to be silent from say, 11PM to 7 AM and NEVER look at it until after you're up the next day (for me, it's never until after I've poured a cup of tea or coffee.) Do NOT use your phone as your alarm clock. you can afford to buy a real one.)

Repeat daily.

Other tips: No caffeine after dinner. No sugar or snacks after dinner. If you must have dessert, do it very soon after dinner. No hard exercise within X hours of bedtime (seems to vary a lot per person, for some reason - experiment and see...) If really having trouble sleeping, music may help - instrumental ONLY - words are your enemy if trying to clear your mind to sleep. If you have Amazon Prime and an Echo, I've found the "Just Breathe" playlist puts me down quickly enough that I'll sometimes use it to provoke a bit deeper sleep for an afternoon nap if I need more than usual recharge from that. Despite (or because of?) it's complexity, baroque classical seems to help, too - kind of the opposite of the previous playlist, so see what works for you. Someone once told me that Bach's Goldberg Variations (I prefer them on harpsichord, Trevor Pinnock's recordings are especially good)were written to help a patron who was having trouble sleeping - it does seem that the intertwining complexity and counterpoint seems to put the mind in a more relaxed state. Use low volume, so the music stopping doesn't wake you up!

BTW, naps of no more than about 20 mins can do wonders for nighttime sleep, too. If your work situation doesn't allow naps, either get creative, find a new job, or just realize you can't nap after all.

As always, find out what works for you - YMMV!

Sleep well. You've got this.