Play some soft, soothing music that will lull you to sleep. There are even cassettes and records designed for that very purpose. Some are specially composed music, others simply have sounds of waves rhythmically breaking, or the steady pattern of a heartbeat.
Of course if you don’t have a record, cassette or CD player that will automatically turn off, we don’t suggest this. If you have to get up and turn it off at the end, you’ve obviously lost its effect.