Bhagavad-gita is the instruction given by Krishna, and Srimad-Bhagavatam is the book containing topics exclusively about Krishna and His devotees. These two books are the special nectar of the words of Krishna.
Srimad Bhagavatam 4.4.44,
The Lord can be known by the mercy of the Lord only, and by no other means.
Srimad Bhagavatam 1.11.39,
This is a sure sign of spiritual strength, for where there is preaching there must be life. Please go on increasing more and more book distribution. You are working in the right direction.
[Letter to Abhirama 9 Jan 1976]
Vaishnava etiquette is a combination of two words: Vaisnava and Etiquette. Vaishnava means the pure devotee of the Lord and Etiquette means the activity and behaviour of a Vaishnava.