The Upanishads suggested that you should associate in your mind the sound Ome. The silence following this sound can be used to represent Turium, they said. It becomes easier and easier to understand yourself as the one consciousness in which you experience the whole of life - waking, dreaming and deeps.
Swami Sarvapriyananda teaches one of the shortest and most profound upanishads accompanied by Gaudapada's Karika. This lecture covers Karika 22-23 and Mantra 12.