When we do this chanting regularly, there starts a process of purification of mind and heart. There is a big clog of past impressions that we have been carrying; many lives, many burdens. It will take some effort to remove the dust that has got collected, that does not allow us to come in touch with our source and which keeps us rolling in the trap of endless disturbing thoughts. So when we chant or sing these mantras the cleansing of the heart takes place,gradually the thoughts go away and mind becomes calm.
And lets remember that when we start to clean a room that has remained closed for ages, the dusting process makes us a little comfortable,so here as well when you start chanting,out of nowhere you may feel some guilt feeling, anger or kind of discomfort but do not stop, just keep doing it, keep repeating it unceasingly and slowly but inevitably the things will begin to change.
There are methods in Indian theology like sitting silence for long, breathing techniques or studying the Shastras but in today's age people find it really difficult to follow them, there is a lot of negative energy in us because of stress and bad food habits, so it becomes almost impossible to do so many yogic postures etc, but here you just have to put the sacred words on your tongue and guess what, thats it. People could follow the other paths as in earlier times as their bodies were much more purer and stronger than those of our times.
Chanting is the simplest of methods, you can chant loudly,slowly, sing it with musical instruments and do it while you are sitting,walking,talking,alone or with a group of people. Just do it. There are many mantras in our scriptures, one can go a Guru or spiritual master and take the mantra from Him/Her or there are some which can be chanted by anyone even if they are not initiated into a particular order.
There is a Shabad (hymn) in Gurbani which goes thus: Naam Niranjan nir Narayan, rasna simrat paap balayan. The name of the God 'Narayan' is an ambrosial water, just put it on your tongue and all the sins will get washed off. A great saint from Bengal, Thakur Sitaram Das Omkarnath has written in the glory of the name: "Listen dearest! The Name is devotion, the Name is ecstasy, the Name is love. 'I Myself am the Name, the Name is Myself.' You have had Me in the form of the Name. Fear no more. The Name is the object of meditation, the Name is the act of meditation, the Name is the object of spiritual exercise, the Name is the act of spiritual exercise, the Name is the process, the Name is the product, the Name is the recipient, the Name is the object of worship, the Name is the act of worship, the Name is offering in worship. Look, dear! I am very fond of the tears shed by the devotee whose heart has been dissolved and who wears the visible wreath of ecstatic thrill. With tears of the eyes, say the Name, say the Name, offering the Name in worship. Fear Not,Fear Not,Fear Not."
Chaitanya Mahaprabhu, another spiritual gem from Bengal writes: "O my Lord, Your holy name alone can render all benediction to living beings, and thus You have hundreds and millions of names like Krishna and Govinda. In these transcendental names You have invested all Your transcendental energies. There are not even hard and fast rules for chanting these names. O my Lord, out of kindness. You enable us to easily approach You by Your holy names."
So chant as much as you can and advise it to others, no need to bother about what is the correct path, just fill your mouth with the name of God and the right path will come to you by itself. Chant and be happy, everything else will be taken care of.