I always go straight to sleep as soon as my head hits the pillow, but I know some people toss and turn, especially in the wilds. Here’s how to go out to it just like flicking a switch:
1. Before you begin, place the tip of your tongue on the roof of your mouth just above your teeth and keep it there throughout the exercise.
2. Exhale completely through your mouth quite forcefully so you make a “whoosh” sound.
3. Close your mouth and inhale quietly and softly through your nose for a mental count of four.
4. Hold your breath and count to seven.
5. Next, exhale completely through your mouth, making another whoosh sound for eight seconds in one large breath.
6. Now inhale again and repeat the cycle three times for a total of four breaths.
A good pillow is a big help. here’s one I use:
Another useful breathing technique: http://www.theultralighthiker.com/catching-your-breath-walking-uphill/