Blackout curtains. I and I imagine, most people, are sensitive to light. Blackout curtains prevent light from reaching your eyes, resulting in your getting more sleep.
Eyemasks are also effective, but (1) you have to tolerate having something on your face and (2) they can get dislodged while you are sleeping, rendering them ineffective.
Eyemasks are also effective, but (1) you have to tolerate having something on your face and (2) they can get dislodged while you are sleeping, rendering them ineffective.