If we were looking at kids with sleep trouble who stayed up late with bright screens blasting hyper-stimulative entertainment and carnival-bright indoor room lighting,
and we believed that sleep quality and quantity had gotten worse for kids over the decades as room lighting had gotten brighter (y'all seen a '50s or earlier house with electric lighting that hasn't been re-wired? They're not lit up like a modern house, usually, and lower-light set-ups continued to be fairly common, if less the
overwhelming norm, through at least the 70s) and electronic screens per house had moved from "none" to "one tiny one" to "several per person, in many sizes", the
very first thing we'd do is cut off their electronic screen-having devices—all of them, not just cell phones,
all of them—and lighting brighter than ~100 lumen per room
strictly at sundown. "Well of course they can't sleep!", we'd say, tutting and looking on with the authority and perspective of parents.
"But I'm having trouble sleeping and I'm bored, can't I just watch a couple episodes of something?" they'd say. NO, we'd say. "Well how about I work on some homework on my computer?" NO. "Alright, well I guess I'll text my friends" NO. "But..." NO.
And if sleep across the population of kids had indeed been getting worse over that time period, I'd bet that'd fix it for most of them.
We have trouble enforcing rules like that on ourselves, though, and maybe even trouble recognizing what's surely suspect #1 in any kind of declining sleep quality epidemic.
(as for any "tricks" we're all sharing, the ones I've had success with are: a loud and powerful fan for air circulation and noise-masking; keeping the thermostat for our bedrooms quite low at night, even in the Summer; heavy curtains; and a weighted blanket, which if nothing else is very good at keeping any sheets or other blankets under it in place all night—and yes, I'm terrible at sticking to the obvious solution above, just like everyone else, but damned if it doesn't work like a charm on my stupid "I think I might have an abnormal sleep cycle LOL yeah, must be that, not all the low-effort hyper-stimulative entertainment" ass)