Japa advice from Srila Prabhupada
Posted on September 27, 2017
Chanting japa should be done early in the morning with full concentration preferably during the Brahma Muhurta time. Concentrate fully on the sound vibration of the mantra, pronouncing each name distinctly and gradually your speed in chanting will increase naturally. Do not worry so much about chanting fast, most important is the hearing.
Srila Prabhupada, letter, Jan 6th 1972