I remembered something I used to do when I was younger, it's a small thing that makes a big impact.
I used to do something out of my routine everyday, like showering in the dark or writing with my left hand (I'm a righty).
It makes you re-think obvious things you're doing, how amazing it is to be able to put down on paper couple of lines that we recognize as a sound :)
If you want some ideas here is a good place to browse and pick:
A few I really liked:
Blindfold Yourself for a Day
Talk To A Stranger
Read The Dictionary