First of all, there should be a clear conception of the Aim of one's life.
The Aim should be such that it should not be subject to subsequent change of opinion or transcendence by some other thought, feeling or experience. It means, the Aim should be ultimate, and there should be nothing beyond that.
It will be clear that, since the ultimate Aim is single, and set clearly before one's mind, everything else in the world becomes an instrument, an auxiliary or an accessory to the fulfilment of this Aim.
It is possible to make the mistake that only certain things in the world are aids in the realisation of one's Aim of life, and that others are obstacles. But this is not true, because everything in the world is interconnected and it is not possible to divide the necessary from the unnecessary, the good from the bad, etc., except in a purely relative sense. The so-called unnecessary items or the useless ones are those whose subtle connection with our central purpose in life is not clear to our minds. This happens, when our minds are carried away by sudden emotions or spurts of enthusiasm.
All this would mean that it is not advisable or practicable to ignore any aspect of life totally, as if it is completely irrelevant to the purpose of one's life. But here begins the difficulty in the practice of sadhana, because it is not humanly possible to consider every aspect of a situation when one tries to understand it.
The solution is the training which one has to receive under a competent Teacher, who alone can suggest methods of entertaining such a comprehensive vision of things, which is the precondition of a true spiritual life, or a life of higher meditation.
There are economic and material needs as well as vital longings of the human nature which have to be paid their due, at the proper time and in the proper proportions, not with the intention of acquiring comfort and satisfaction to one's self, but with a view to the sublimation of all personal desires or urges, whether physical, vital or psychological. An utter ignorance of this fact may prove to be a sort of hindrance to one's further practice on the path of Sadhana.
It is, of course, necessary that one should live a life of reasonable seclusion under the guidance of a master until such time when one can stand on one's own legs and think independently without help from anyone.
But, one should, now and then, test one's ability to counteract one's reactions to the atmosphere even when one is in the midst of intractable and irreconcilable surroundings. Seclusion should not mean a kind of self-hypnotism or hibernation and an incapacity to face the atmosphere around.
It should also not mean that one should be incapable of living in seclusion alone to oneself, when the occasion for it comes. In short, the ideal should be achievement of an equanimous attitude to circumstances, whether one is alone to oneself, or one is in the midst of an irreconcilable social atmosphere.
While in seclusion the mind should not be allowed to go back to the circumstances of one's family life, official career or to problems which are likely to disturb the concentration of the mind on God, because the pressure of these earlier experiences may sometimes prove itself to be greater in intensity than one's love of God.
It is impossible to concentrate on God unless one has a firm conviction and faith that whatever one expects in this world can also be had from God; nay, much more than all these things which the world has as its treasures and values.
It is difficult to have the vision of one's Aim of Life, when the mind goes out of meditation to whatever it longs for in the world. Hence, a deep study of the Upanishads and the Bhagavad Gita, the Srimad-Bhagavata and such other scriptures is necessary to drive into the mind the conviction about the Supremacy of God.
Study or svadhyaya, japa of mantras, and meditation are the three main aspects of spiritual practice.
Svadhyaya does not mean study of any book that one may find anywhere at any time. It means a continued and regular study, daily, of selected holy texts, or even a single text, from among those that have been suggested above. A study in this manner, done at a fixed time, every day, for a fixed duration, will bring the expected result.
The japa of the mantra should, in the beginning, be done with a little sound in the mouth so that the mind may not go here and there towards different things. The loud chant of the mantra will bring the mind back to the point of concentration. Later on, the japa can be only with movement of lips, but without making any sound. In the end, the japa can be only mental, provided that the mind does not wander during the mental japa.
A convenient duration, say, half an hour, or one hour, should be set up at different times, so that the daily sadhana should be at least for three hours a day. It can be increased according to one's capacity, as days pass.
During japa, the mind should think of the meaning of the mantra, the surrender of oneself to the Deity of the mantra, and finally, the communion of oneself with that Great Deity. Effort should be put forth to entertain this deep feeling during japa, every day.
Meditation can be either combined with japa, or it can be independent of japa. Meditation with japa means the mental repetition of the mantra and, also, at the same time, meditating deeply on the meaning of the mantra, as mentioned above.
Meditation without japa is t higher stage where the mind gets so much absorbed in the thought of God, surrender to God and union with God, that in this meditation japa automatically stops. This is the highest state of Meditation.
Throughout one's sadhana, it is necessary to feel the oneness of oneself and the universe with God.