I'll share what works for me. I focus on my breathing by thinking 'inhale' as I inhale, and 'exhale' as I exhale... and repeat... until I am asleep. It seems to work consistently and very quickly for me but may take a little effort at first. (Perhaps it works because it's so ***boring*** :-) Another option is to imagine your favorite place/image/person/etc: the sights, sounds, and sensations. For me, a beach, warm white sand, the warmth of the sun, the sound of the waves...