Lighting runs your body clock harder than your alarm does. Sounds dramatic, yet your brain treats brightness and color as a time stamp. Blue-rich light says "morning, get moving." Warm, low light says "wrap it up." Feed it the wrong signals and you'll lie awake at midnight, wondering why your head feels like a floodlit stadium. 
Morning: go bright Sunlight is the strongest cue you can give. Ten to twenty minutes outdoors after waking beats any indoor bulb, gray day or not. Cloud cover still delivers thousands of lux, far more than a typical living room. No yard? Throw the curtains open and park by the window with your coffee. If winter mornings are pitch black where you live, a bright daylight lamp on your desk can stand in. Evening: keep it low About two hours before bed, drop the brightness. Switch off overhead fixtures and lean on lamps. Choose bulbs near 2200 to 2700 kelvin, the amber glow of a candle flame. Many smart bulbs shift on a schedule, so the house slides toward sunset without you thinking about it. Cool white at ten at night is like espresso after dinner. Technically allowed. Probably a mistake. The screen problem Phones and tablets pour blue-leaning light straight into your eyes from about a foot away. Night modes help a bit. Lower brightness helps more. Leaving the phone in another room helps most, though I know that's the hardest advice to swallow. A friend of mine bought an old-fashioned alarm clock for exactly this reason, and she says her evenings turned oddly long and pleasant. Your bedroom Keep it dark. Really dark. my ever lights Blackout curtains do the job, and a sleep mask does too if you rent and can't hang heavy drapes. Cover tiny standby LEDs with a dab of tape. If you need a path to the bathroom, use a motion-activated nightlight in dim red or amber, mounted low on the wall, so you don't blast your eyes wide open at three in the morning. If you work nights Your schedule might fight the sun. Fine. Use bright light during your "morning," whenever that falls, and wear dark glasses on the commute home after a night shift. Tell your household that your bedroom is a cave during your sleeping hours. Be firm, be kind, bribe with snacks if needed.
Morning: go bright Sunlight is the strongest cue you can give. Ten to twenty minutes outdoors after waking beats any indoor bulb, gray day or not. Cloud cover still delivers thousands of lux, far more than a typical living room. No yard? Throw the curtains open and park by the window with your coffee. If winter mornings are pitch black where you live, a bright daylight lamp on your desk can stand in. Evening: keep it low About two hours before bed, drop the brightness. Switch off overhead fixtures and lean on lamps. Choose bulbs near 2200 to 2700 kelvin, the amber glow of a candle flame. Many smart bulbs shift on a schedule, so the house slides toward sunset without you thinking about it. Cool white at ten at night is like espresso after dinner. Technically allowed. Probably a mistake. The screen problem Phones and tablets pour blue-leaning light straight into your eyes from about a foot away. Night modes help a bit. Lower brightness helps more. Leaving the phone in another room helps most, though I know that's the hardest advice to swallow. A friend of mine bought an old-fashioned alarm clock for exactly this reason, and she says her evenings turned oddly long and pleasant. Your bedroom Keep it dark. Really dark. my ever lights Blackout curtains do the job, and a sleep mask does too if you rent and can't hang heavy drapes. Cover tiny standby LEDs with a dab of tape. If you need a path to the bathroom, use a motion-activated nightlight in dim red or amber, mounted low on the wall, so you don't blast your eyes wide open at three in the morning. If you work nights Your schedule might fight the sun. Fine. Use bright light during your "morning," whenever that falls, and wear dark glasses on the commute home after a night shift. Tell your household that your bedroom is a cave during your sleeping hours. Be firm, be kind, bribe with snacks if needed.