To fall asleep?

Think Sa on inhale and Ha on exhale can work, or I count backwards from 100 in Spanish, starting over when I forget where I am. Yin yoga is good too, forward folds calm the nervous system.

To do something else, when it seems sleep is not possible or desirable? Emotional stress? Get out of bed & go for a night walk, or even a run. Exercise. Get physically exhausted if possible.