After you have practised Pratyahara for a time, take the next step, the Dharana, holding the mind to certain points. What is meant by holding the mind to certain points? Forcing the mind to feel certain parts of the body to the exclusion of others.
For instance, try to feel only the hand, to the exclusion of other parts of the body. When the Chitta, or mind – stuff, is confined and limited to a certain place it is Dharana. This Dharana is of various sorts, and along with it, it is better to have a little play of the imagination. For instance, the mind should be made to think of one point in the heart. That is very difficult; an easier way is to imagine a lotus there. That lotus is full of light, effulgent light. Put the mind there. Or think of the lotus in the brain as full of light, or of the different centres in the Sushumna mentioned before. The Yogi must always practise. He should try to live alone; the companionship of different sorts of people distracts the mind; he should not speak much, because to speak distracts the mind; not work much, because too much work distracts the mind; the mind cannot be controlled after a whole day’s hard work. One observing the above rules becomes a Yogi.
Also Read The Eight Limbs Of Yoga