While doing Japa the following rules should be observed.
Take a bath, or wash your hands, feet, face and mouth before sitting for Japa in the morning. At other times this is not absolutely necessary. Do Japa whenever you have leisure, specially during the Sandhyas or the junctions of the day (morning, noon and evening) and before going to bed.
A comfortable Asana (Padmasana, Siddhasana, etc.) helps to make the mind also steady, controls Rajas and aids concentration.
Face the North or East. This exercises a subtle influence and enhances the efficacy of Japa.
Before commencing the Japa repeat elevating prayers invoking the aid of your Ishta-Devata. This induces proper Sattvic Bhava.
Repeat your Ishta Mantra 108 or 1080 times daily (one to 10 Malas). Gradually increase this.
Think of the meaning of the Mantra while repeating it.
Pronounce each letter of the Mantra correctly and distinctly. Do not repeat it too fast or too slow. Increase the speed only when the mind wanders.
Variety in Japa is necessary to sustain interest, avoid fatigue, and counteract monotony. Repeat aloud for a time, then hum the Mantra and repeat mentally sometimes.
During Japa you should be alert and vigilant. This is important. Otherwise after a time the mind will begin to wander and drowsiness will overcome you.
Keep a picture of your Ishtha-Devata in front. Side by side with Japa think of the Lord as present before you and picture His entrancing, beautiful form. This practice aids tremendously to the efficacy or power of your Sadhana.
Feel that your heart is being purified and the mind is becoming steady by the power of the Mantra with the grace of God. God and His Name are identical.
After Japa is over do not immediately leave the place and do not mix with everyone nor plunge into worldly activity. Sit very quietly for about 10 minutes at least, humming some prayer, remembering the Lord or reflecting upon His infinite love. Then after devout prostrations, leave the place and commence your routine duties. Spiritual vibrations will be intact.
Keep your Mantra a secret. Never disclose it to anyone.
Carry on the current of Japa mentally even at other times, in whatever works you may be engaged.