For those who believe in God, a symbolical name, such as Om or other sacred words received from a Guru, will be very helpful. Om is the greatest, meaning the Absolute. Meditating on the meaning of these holy names while repeating them is the chief practice.
His manifesting word is Om.
Ishvara is the Atman as seen or grasped by mind. His highest name is Om; so repeat it, meditate on it, and think of all its wonderful nature and attributes. Repeating the Om continually is the only true worship. It is not a word, it is God Himself.