Our protective sleep center in the brain will work if we give it half a chance. As we change out of our day clothes we can tell ourselves we are removing our cares, worries, etc. right along with them and putting on the calm, the peaceful, the tranquil. We enter a realm of quiet and relief from the torments, drop them with the clothes. No-one can distress or interrupt us, the birds are sleeping as is everyone else. We are given a reprieve to heal ourself, enjoy our pillows and blanket.
Meditation before bedtime helps too.