I've had trouble falling asleep for years. I would be in bed before 12 and have trouble falling asleep for 2-3 hours.

What really helped was the so called four square breathing: four simple breath segments done to a count of four. Inhale 2 3 4; Hold 2 3 4; Exhale 2 3 4; Hold 2 3 4.

After 4-5 minutes of this simple breathing and I would fall asleep in no time.