The first ten of the twenty items mentioned above are affirmative, and the second ten are prohibitive. In the Bhakti-rasāmṛta-sindhu, compiled by Śrīla Rūpa Gosvāmī, it is said that one should be very liberal in behavior and should avoid any undesirable activities. Of the twenty regulations, the most important are the first three: to accept the shelter of a bona fide spiritual master, be initiated by him, and serve him.
In addition to these twenty, there are thirty-five more items of devotional service, and they can be analyzed as follows: (1) hearing about the Lord, (2) chanting about Him, (3) remembering Him, (4) worshiping Him, (5) praying to Him, (6) serving Him, (7) engaging as His servitor, (8) being friendly toward Him, (9) offering everything to Him, (10) dancing before the Deity, (11) singing before the Deity, (12) informing the Deity of one's thoughts, (13) offering obeisances to the Deity, (14) standing up to show respect to the Deity and the devotees, (15) following a devotee when he gets up to go to the door, (16) entering the temple of the Lord, (17) circumambulating the temple of the Lord, (18) reciting prayers to the Lord, (19) vibrating hymns in His honor, (20) performing saṅkīrtana, or congregational chanting of the holy name, (21) smelling the incense and flowers offered to the Deity, (22) accepting prasādam (food offered to Kṛṣṇa), (23) attending the ārati ceremony, (24) seeing the Deity, (25) offering palatable foodstuffs to the Lord, (26) meditating on the Lord, (27) offering water to the tulasī tree, (28) offering respect to the Vaiṣṇavas or advanced devotees, (29) living in Mathurā or Vṛndāvana, (30) understanding Śrīmad-Bhāgavatam, (31) trying one's utmost to attain Kṛṣṇa, (32) expecting the mercy of Kṛṣṇa, (33) joining with devotees in performing Kṛṣṇa's ceremonial functions, (34) surrendering to the Lord in all respects, (35) observing different ceremonial functions and vows.