Let your brain focus on the sounds, this is what our brain is made for, while it focuses on the sounds, no thoughts will present them self. Focusing our brain on other things, a fire, a sound or sounds in general is a great method to realize the detachment between consciousness and the primitive brain.

The Buddhists call it "the monkey brain" made for survival in the jungle, always alert :)

One other tip I´ve used, is to have an alarm clock around 4-5 am and meditate 1 hour if you do not fall asleep, it will be both more quiet and you are in a relaxed state :)

Peace and I wish you the best of luck!