In Bhakti-rasāmṛta-sindhu compiled by Śrī Rūpa Gosvāmī it is said that one should be very liberal in behavior and should avoid any undesirable activities. The most important affirmative points are that one should accept the shelter of a bona fide spiritual master, be initiated by him and serve him.
In addition to these, there are thirty-five items of devotional service, and they can be analyzed as follows: (1) hearing, (2) chanting, (3) remembering, (4) worshiping, (5) praying, (6) serving, (7) engaging as a servitor, (8) being friendly, (9) offering everything, (10) dancing before the Deity, (11) singing, (12) informing, (13) offering obeisances, (14) standing up to show respect to 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) reading prayers, (19) vibrating hymns, (20) performing saṅkīrtana, or congregational chanting, (21) smelling the incense and flowers offered to the Deity, (22) accepting prasāda (food offered to Kṛṣṇa), (23) attending the ārātrika ceremony, (24) seeing the Deity, (25) offering palatable foodstuffs to the Lord, (26) meditating, (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) performing ceremonial functions with the devotees of Kṛṣṇa, (34) surrendering in all respects, (35) observing different ceremonial functions.