Every six months a new viral sleep tip makes the rounds. Most of them are unfounded. A few of them are real interventions wearing influencer clothing. Sorting one from the other requires reading the actual literature, which I've been doing for a year now.
None of this is medical advice. It is a literature summary.
What's well-supported
Consistent wake time. Of all the interventions studied, the one with the most robust replication is keeping the same wake time seven days a week, including weekends. Sleep onset latency improves on a timescale of weeks, not nights.
Light exposure within the first hour of waking. Morning light is the single largest cue for the circadian system. The evidence here is unusually solid for sleep research, which tends to be noisy.
Cool bedroom temperature. The window is roughly 18 to 20 degrees Celsius for most adults. The mechanism — a small drop in core body temperature signals sleep onset — is well-characterized.