Q: What is the difference between Japa and meditation?
A: Japa is the silent repetition of the Name of the Lord. Meditation is the constant flow of one idea of God. When you repeat ‘Om Namo Narayanaya’ it is Japa of Vishnu Mantra. When you think of conch, discus, mace and lotus-flower in the hands of Vishnu, His earrings, crown on His head, His yellow silk Pitambara, etc., it is meditation. When you think of the attributes of God such as Omniscience, Omnipotence, etc., it is also meditation.
Q: Give me practical instructions as to how to meditate.
A: Sit in Padma or Siddha Asana in a solitary room, keep the head, neck and trunk in one straight line. Close your eyes. Imagine that a big effulgent sun is shining in the chambers of your heart. Place the picture of Lord Vishnu in the centre of a lotus flower. Locate the picture now in the centre of the blazing sun. Repeat His Mantra “Om Namo Narayanaya” mentally and see His image in your heart mentally from foot to head, His weapons in the hands, etc. Shut off all other worldly ideas.
Q: When I meditate, my head becomes heavy. How to remove this?
A: Apply Amalaka oil to the head and take cold bath. Dash some cold water on the head before you sit for meditation. You will be all right. Do not wrestle with the mind.
Q: Is seclusion necessary?
A: Absolutely necessary. It is indispensable.
Q: How long should I remain in seclusion?
A: For full three years.
(Source: pgs. 136-137, Concentration and Meditation)