The unfamiliar environment of a hotel room makes it easy to misplace important stuff like your keys, wallet or phone. Keep it all organised by laying a hand towel on a convenient surface and make a habit of placing all important items in this one spot.
Image from koenvandeneeckhout
In a recent interview, Daniel Levitin, author of The Organised Mind, explains how this helps:
What a lot of people do when they're travelling and they end up in hotels, is they will take one of the hand towels from the bathroom, spread it out on the counter or on a table, and that becomes the de facto place for all the things that you have a place for at home. Put your keys there, your wallet, your passport, or anything else you don't want to forget. They're all in one spot, instead of scattered around the room, and they're in a spot that you've created.
For more tips on how to be organised, check out the radio interview, linked below. You can hear this tip at about 9:15 (not to mention a quick interview with Lifehacker's own Whitson Gordon later in the show).