If you often leave items in hotel rooms, remind yourself by writing it down -- but write it on a mirror with a dry erase marker instead of on a piece of paper you could easily overlook.

Dry erase markers can be wiped off mirrors easily with toilet paper, napkins, or even a towel, and there won't be scraps of paper everywhere.

You could leave notes to yourself and you can be sure that you'll see those notes later.

Just be careful of bathroom mirrors, because you might accidentally wipe those notes away after showering, if the mirror steams up.