You begin with food. Through ahara shuddhi, by eating pure food, you purify your body. Then just as your gross body needs solid food to maintain its existence, your pranic body needs pranic energy to sustain itself. Senses, mind, ego, and intellect all require their own kind of food.
Sattvic food, which is fresh, light, and nutritious, taken in the appropriate quantities, at the right time, and with the right attitude of mind, provides a pure diet. Similarly, breathing clean air, with a regulated dominance of right and left nostrils, nourishes the pranic body.
Maintaining positive thoughts in a cheerful mind provides nutritious food to the mental body.
Constant awareness of the fact that anything indicated by the words 'my' and 'mine' belongs to prakriti-whereas the truth indicated by 'I' is pure consciousness-supplies nutritious food to the ego. Purify yourself by maintaining the constant awareness that all objects belong to nature and that it is a mistake to identify with them.
Similarly, remaining aware of your pure existence, consciousness, and bliss is the way to supply food to the anandamaya kosha, the body made of bliss.
By creating a bridge between different aspects of our being and strengthening rather than weakening each of these aspects, we attain perfect realization o the Self. Know yourself at every level and find yourself perfect in every respect. That is the only way to attain true happiness.
You purify your external and internal life by purifying the food you provide to every level of your being. As a result your memory becomes sharp and stable; then you begin to glimpse your inner Self and eventually come to know it well.
As these glimpses of your inner Self becomes brighter and steadier, your attachment to worldly objects and desires for pleasure becomes thinner and weaker. The weaker your desires and attachments, the fewer obstructions they create to the illumination your inner Self. And the fewer obstructions in the light that radiates from within, the brighter you will see yourself both within and without.
Source: Extract from the book Traditions of Himalayan Masters - By Pandit Rajmani Tigunait