Origin & Meaning

A mantra is a syllable or word, usually without any particular meaning, that is repeated for the purpose of focusing your mind. It is not an affirmation used to convince yourself of something.

Some meditation teachers insist that both the choice of word, and its correct pronunciation, is very important, due to the “vibration” associated to the sound and meaning, and that for this reason an initiation into it is essential. Others say that the mantra itself is only a tool to focus the mind, and the chosen word is completely irrelevant.

Mantras are used in Hindu traditions, Buddhist traditions (especially Tibetan and “Pure Land” Buddhism), as well as in Jainism, Sikhism and Daoism (Taoism). Some people call mantra meditation “om meditation”, but that is just one of the mantras that can be used. A more devotion oriented practice of mantras is called japa, and consists of repeating sacred sounds (name of God) with love.
 
How to do it

As most type of meditations, it is usually practiced sitting with spine erect, and eyes closed. The practitioner then repeats the mantra in his mind, silently, over and over again during the whole session.

Sometimes this practice is coupled with being aware of the breathing or coordinating with it. In other exercises, the mantra is actually whispered very lightly and softly, as an aid to concentration.

Here are some of the most well-known mantras from the Hindu tradition:

    om
    so-ham
    om namah shivaya
    om mani padme hum
    rama
    yam
    ham

You may practice for a certain period of time, or for a set number of “repetitions” – traditionally 108 or 1008. In the latter case, beads are typically used for keeping count.

As the practice deepens, you may find that the mantra continues “by itself” like the humming of the mind. Or the mantra may even disappear, and you are left in a state of deep inner peace.

Information Source: http://liveanddare.com