Sleep is easily overlooked when we think about improving our health. Often people turn towards eating habits or exercise (very important!). We forget we are very simple complex creatures! Sleep is an imperative factor for your health. 
The Following is directly derived from Reclaiming Life after Trauma: Healing PTSD with Cognitive-Behavioral Therapy and Yoga By: Daniel Mintie & Julie K. Staples

Shabda Kriya is a yogic practice that two Harvard University studies have demonstarted to be effective for insomnia. Shabad Kriya may be practiced any time of the day, the best time being just before going bed. It is said that if it is practiced regularly, sleep will be deep and relaxed and the nerves will regenerate. This meditation uses the mantra Sat nam broken into four syllables-Sa Ta Na Ma- and recited silently. The "a" in each of these syllables sounds like "ah". The meaning of the syllables are as follows:

*Sa: Infinity
*Ta: Life(birth of form from Infinity)
*Na: Death (or transformation)
*Ma: Rebirth

Sa-Ta-Na-Ma describes the continuous cycle of life and creation.

This mediation also uses the silent mantra "Wahe guru". Wahe guru means" I am in ecstasy when I experience the indescribable wisdom". It expresses the indescribable expereince of going from darkness to light (from ignorance to true understanding).

Left nostril breathing may also help you relax and fall asleep. Left nostril breathing is associated with the ida energy channel and promotes relaxation, calm, sensitivity, and empathy. Research shows that left nostril breathing can also reduce sympathetic nervous system activity. We have a natural nasal cycle that switches predominant airflow between nostrils every one and half to four hours. The left nostril dominance of this cycle can sometimes be induced simply by lying on your right side, whcih may help you fall asleep.

Sweet Dreams!