OK, so what you want to do is stay awake for atleast 20 hours, sleep for like 5 hours then wake up, do this for a while then pick a time to go to bed, now you gotta drink some sleepy time tea, set a few alarms and fall asleep, you should sleep for about 8 hours, and wake up refreshed, now repeat this every night until you don't need the tea.

You gotta overload your circadian rhythm to reset it.

As others have said, it's simply a matter of discipline and getting used to it. But that doesn't necessarily mean you'll become a morning person. How you wake up and when you wake up are two different things. I'm a morning person in that I wake up easily, but I go to sleep at 1 and wake up at 9.

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.

Enlarge your prostate.

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.

Requires rote repetition

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

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.

What worked for me: marry one of those people

Marry a teacher.

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.