I've never gotten used to wearing a mask, so when I travel I make every effort to get a room away from the street so I'm less likely to have either street lights or the hotel's own lights shining in the window. I unplug everything I can, and I bring tape for the rest. Nightlights built into bathroom power outlets have been a particularly annoying trend lately, and most kinds of tape don't completely block the light themselves, but the tape can hold whatever thickness of paper or cardboard I need. Band aids will work in a pinch, but tape is cheaper.