If you want to know how to get a better night's sleep, then Ps.3 might help you. The Psalmist has been troubled by wicked people, and his problems have increased and many have risen up against him, v.1. He is being attacked on every side and his problems are becoming worse and harder to deal with. His neighbours are taunting him by saying of him that God will not help him, v.2. Ridicule and mockery abound, and these are hurtful. It is very difficult to switch off when such things are like an ear-worm in your head.
Yet, this man knows that the LORD is his shield of protection to keep these bad thoughts from him, v.3. He prayed to the Lord and He heard him, v.4. Our God hears and answers prayer from His children. Try Him and see for yourself.
Then with God as his shield, his glory and his encourager, he can place his head on his pillow, and enjoy a good night's sleep, v.5. With God at your side, you can sleep in peace. Then in the morning when you wake up, you feel refreshed for the Lord gave him the sustenance he needed. With such resources, he fears not the greatest army, v.6,7. He knows where his salvation lies - with and in the LORD, v.8.
To know really good sleep in the midst of great problems, trust the LORD as your shield and defender, call out to Him in prayer, and experience His grace to you.
Look at this website and discover some practical hints that might help you get better sleep. Tie these in with what the Psalmist says in Ps.3, and see the difference.