Let me see, only ones I have used.

Don't work:

Pinch your nose, close eyes, look back and forth for text and clock, look at the shadows, motions and actions of people, movement of other objects, behaviour of animals, sun, clouds speed, feeling of air, smell of stuff, hearing radio, music, tasting some stuff, night, moonlight, synchronization between movement of the mouth and the sound that comes out of it, looking at mirrors, my hair, location of objects on my room/school/street, stuff that is within shops and the owners/people buying in them and mental RC, like wondering about what I did before.

Work:

Gravity and Air pressure.