Sleep

I'm not a doctor, but here are some things I've done that have improved my sleep in no particular order:

Wear a sleep mask
Use earplugs
Have blackout curtains
Cover lights with tape
Use automated smart blinds/curtains/lights
Keep a consistent sleep schedule
Use a CPAP machine [1]
Avoid caffeine after noon
Use melatonin on occasion, but buy the lowest dose available
Use an ergonomic head and knee pillow [2]
Create background noise with a phone, fan, or air filter
Use night mode on all devices [3] [4]
New mattress [5]

References