Enlarge your prostate.

It helps to establish a routine for going to bed. For example, set a nightly reminder on your phone 15-30 minutes before bedtime that it's time to wind things down. Don't have anything caffeinated after 5 pm or so.

Get a herding dog... seriously mine keeps me on this sleep schedule. She tells me when to go to bed and is my alarm clock in the morning.

Adjust the times at which you eat, and make sure those times are consistent. Sleeping habits will follow way more easily if you adjust eating times along with them.

Skip one night of sleep, go to bed at your target hour, pref an hour or two before.

wake up at 4 - 6 am

Go to bed at 9, fall asleep at 10

For me it was lockdown went to bed early after work out of sheer bordem. Still trying to break out of that routine.

Of course it doesn't help when my dog loves that routine and gets pissed off if not in bed by 8

Requires rote repetition

What worked for me: marry one of those people

Just grow older. At 45 you'll start turning into one automatically

I go through this at the beginning of every school year. All it really takes is about two weeks of being forced to wake up at 6am.

It's a suppository.

Marry a teacher.