I've had a lot of sleep problems in my life. I haven't solved them completely, but I've largely controlled them with a basket of measures. I wear a sleep mask, I get ready for bed around the same time every night, I only drink coffee before noon, I drink the same amount of caffeine every day, I go for a walk first-thing in the morning, I limit my alcohol intake, I try to keep my room cold when I sleep, I don't eat really heavy meals right before bed.

I don't follow this religiously - I'll stay out later and drink with my friends. But doing this as much as possible, and reverting to the routine when I stray, has improved the consistency and quality of my sleep.

Take advantage of the Circadian rhythm. Your body reacts to sunlight. Go outside soon after you wake up. I haven't set an alarm clock in years, now I just naturally wake up around the same time every day.

Sleep is high-variance, so any single measure you take will be difficult to notice. But if you create a system and stick to it, your body can probably adjust to any cycle you want.