I am a big believer in getting a good night's sleep when traveling. This has been made easier by the move to upgrade bedding, led by Marriott if I am not mistaken. But even on a "plush" bed I will have trouble sleeping if the room is not dark. This is especially important when you have shifted time zones and want to acclimate to the new zone.
Of course, most decent hotels provide light-blocking drapes/curtains, but for some reason I have yet to fathom, these often fail to close all the way. The result: the lights from the parking lot keep you awake; or a shaft of blinding sunlight strikes your face at 6:30AM when you really needed to sleep until 8. The answer: binder clips (medium). These are the metal spring clips you get for just pennies a piece at the office supply store. I have had great luck in keeping drapes from drifting apart with just one or two of these clips applied to the inter-folded edges of the fabric. Slip a few into your bag before you head out.
Another room darkening trick is to roll up a surplus part of the bedding (one of those foo-foo decorative cover bits for which I don't even have a vocabulary) and put it across the bottom of the hotel room door, you know, across that yawning gap which doesn't seem too bad when you first turn out the lights, but slowly expands to admit enough light to read by.