In brief, I have been a lifelong nightowl with serious problems sleeping for many years:
Melatonin (can cause serious stomach irritation!! Beware!!!)
No screen two hours before bed
Bedroom only for sleep and um .....
Darkness
Quiet
No caffeine after lunch
For me, all of that standard advice combined does not amount to a hill of beans compared to: Getting up at about the same time every day!
For years, I thought I could get away with sleeping stupid late on the weekends and getting up at a normal time during the week. I finally cut it out a few years ago, and resolved to get up at about the same time every day, and it made all the difference in the world. I get up at around 10 or so on days I need to go to work (flexible schedule) and about 11 on weekends (Child-free lifestyle WOO HOO!). It works better than all that other advice combined times a hundred. I rarely have problems sleeping now, and even when I do, I have had enough sleep the previous nights, it does not really affect me that much, if at all.
OH yes, and earplugs!!! I loathe noise, and the gates of hell open up around seven or eight: Revving up the Harley, lawnmower, BEEP BEEEP BEEEP trucks reversing, chainsaw, circular saw, leafblower, screaming kids, barking fleabag dogs, bondo beaters (with the "subwoofer" pounding out sonic turds at 50 Hz), etc. Insert Hearos blue maximum attenuation = back to sweet sweet sleep!