Also, if you're going to put something somewhere that's not in its place, put it in a place that you'll HAVE to clean soon. I had a lot of success putting all my school-related stuff on my bed throughout the day in high school because I was guaranteed to pack it all up into my backpack because I had to use the bed to sleep.
Repositories are awesome, and we should have more of them.
I recently completed BJ Fogg's Tiny Habits, and it's a pretty lightweight way to install new habits (recommended). However, I realized I could use a better repository of useful habits.
So, please use this thread to suggest habits that you've found useful. Bonus points for evidence/anecdata of usefulness.
Obviously, 1 habit per comment makes upvotes a clearer signal of collective approval.