Taken from the book:Household Feng-Shui.
"When chanting mantra's, you should use your mind
power to transmit and instill the sound and it's frequency into your heart chakra.
While you are chanting a mantra 108 times, do the following visualization:
Visualize a white lotus inside your heart gradually opening to full bloom. Upon the lotus sits the seed syllable Hum.
The Hum syllable emits a beam of strong white light that travels along your central channel from the heart chakra, through the throat chakra, to the crown chakra. (Chant the Guru's Heart Mantra 108 times.)