Srila Bhaktivinoda Thakura has written: madhava tithi bhakti janani jatane palana kori. Ekadasi is madhava-tithi, Krsna Himself. Holy days like Ekadasi are bhakti janani, the mother of prema-bhakti. We should try to follow it as purely as possible, not eating and drinking many times throughout the day.
If possible, observe it without even drinking water (nirjala), or take a little prasada once in the day if this is not possible. Many old people, who are lean and thin, can observe nirjala Ekadasi ; so why not those of you who are young and strong? Try to observe it like this. However, if by such fasting your head pains and you go to sleep, then what is the use? Try to remember Krsna, associate with Vaisnavas, read the Vedic scriptures, and offer prayers day and night.
One such prayer is:
he krsna karuna sindhu dina bandho jagat pate gopesa gopika kanta radha kanta namo 'stu te. [“I offer my unlimited obeisences unto You, O Krsna! You are the ocean of mercy, friend of the fallen, Lord of creation, and master of the cowherd community. You are Gopi-kanta, beloved of the gopis, and above all You are Radha-kanta, the beloved of Srimati Radhika!”] Observing Ekadasi gives even more spiritual power than brahma-jnana (realization of spirit as separate from matter) and brahma-yoga-samadhi (absorption in the impersonal aspect of God).
February 1997 in Murwillumbah, Australia