How do you sleep better?

Sleep routines, phones in the bedroom, caffeine cut-offs, sleep aids.

Answers by date: 4 records in 4 sources, newest first; the answers above are the current ones. The advice was refined (2020), never reversed, in these records.

date	who	answer	source
2020-06-17	Ali	After reading Atomic Habits and Matthew Walker's Why We Sleep, Ali began putting his phone across the room out of reach, and started sleeping better without phone time and blue light before bed.	How To Boost Productivity Without Apps 00:01:56
2020-06-10 (said on 2020-06-01, implied)	Ali	Ali says caffeine at 3 p.m. is a bit dangerous because it stays in the body for a long time and can reduce the quality of sleep.	Music, Reading and Note-Taking - Productive Day in the Life 00:02:55
2020-06-03	Ali	At about 10 p.m. Ali sets his lights to a warm "relax" scene and turns on Night Shift, because blocking blue light apparently readies the body for sleep, as Matthew Walker says in Why We Sleep.	All the Apps I Use in a Day 00:09:06
2018-05-14	Ali	Without his Kindle Ali found falling asleep a waste of time, lying in bed for half an hour thinking; with it back he sleeps much better, reading until his eyes start to close.	Monthly Favourites #4 - Ali Abdaal 00:08:59

Dates are upload dates, which set the order. Where the speaker gives a different recording date in the video, it is added as "said on YYYY-MM-DD, implied" (derived from the date said in the video).