I used to be a champ at both falling asleep AND waking up, but lately I seem to have lost the ability to fall asleep. Road noise, unpredictable nighttime temperature, mind noise, whatever — after another day cut short due to sleeping badly, I decided to do something about it.
First, I investigated Amazon. A lot of the options seemed to be for car windows; I would still have to cut the clings into the right dimensions; reviews were usually mixed; finally, a disappointed reviewer wrote that he’d hoped to replace the aluminum foil with the cling —
— aluminum foil? I had that, more than I’d ever use. Instant shipping and $0? Sold. How had I never thought of this before?
And thus I spent an hour exercising a skill of my people, hanging aluminum foil. Unlike your regular kitchen backsplash, I was covering a window, one side of which opened; I needed to be careful not to tape the window shut / lose the ventilation, whereas I didn’t care much about the light coming in…
…actually I planned nothing and measured nothing beyond making that realization. Eventually I realized that I could use the screen as a guide for the length of the pane, but it was still very ad hoc. I became an expert at cutting tape. I trusted / ensured that every scrap could be used to fill in a gap elsewhere, and it mostly did work out — I probably ‘wasted’ 6” of foil, and of course it’ll end up getting used.
A darker room isn’t a panacea, but I think it’ll knock out one more thing that could be contributing to sub-par sleep. We’ll see how it goes!
 re: the ‘foil on walls’ stereotype of Chinese immigrants — we cook vegetables (contains water) in hot oil (gets above water’s boiling point). This is how vegetables become delicious in 4 minutes vs 40 minutes of roasting! When water boils in oil, it turns into steam, which expands explosively, splattering the oil that surrounds it.
This phenomenon creates the pleasing sizzling sound, but also puts oil into the air. If it isn’t sucked away by a range hood, it’ll land on your backsplash.
Chinese apartments have range hoods, but American apartment kitchens circa 1995 didn’t seem to have real range hoods by default (you might be so unfortunate to get the tease of a range hood that sucks up your oily splatter and just blows it back out in the same room instead of into the outdoors or building vent).
Hence, a lot of people of my parents’ cohort put foil on the walls to prevent losing the apartment deposit due to a kitchen wall caked in oil.
 I was a champ at waking up by having four semesters of 9am Chinese class — since the dictation quiz was in the first minute of class and it was not possible to make up a missed quiz, you had to be early or exactly on time.