The easiest way for concentration is Japa (continuous repetition of a mantra) of the Name of the Lord. And a very important point to bear in mind in this connection is that perfect concentration is not achieved in just a day; you should never despair and give up your efforts.
Be calm. Be patient. Do not worry yourself if the mind wanders. Be regular in your Japa. Stick to the meditation hour. Slowly the mind will automatically turn toward God. And once it tastes the bliss of the Lord, nothing will be able to shake it.
(Source: ‘May I Answer That’ By Swami Sivananda)
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