~Check in~ with your big toe. How's it feeling? What's it touching? Is it warm or cold? What sensations do you feel in it, right now? Keep it going with your toes, then with the ball of your foot, your heel, and your ankle.
This is the beginning of a ~bodyscan meditation~, and when you're laying in bed with the lights out, can help put you right to sleep. If you have trouble, try following a guided bodyscan meditation for a few nights, like this one or this one.