Essence of essence is humility

Gaudiya Vaishnavism is a branch from the Brahma-Madhwa parampara. The uniqueness of this branch is that it imbibes the mood of Radha and sweetness of Krishna. No other sampradaya focuses on these two qualities much. Sripad Madhavendra Puri is the initiator of this mood and Lord Chaitanya accepted Madhvendra Puri as His Param Guru. Then Mahaprabhu planted this seed all over India and Srila Prabhupada all over the world.

The recommended method to achieve the mood of Radha as given by Mahaprabhu is Nama-sankirtanam. Therefore, (1) Externally speaking, the essence is chanting (2) Internally speaking, the essence is love in separation of God in the mood of Radha. the essence for both is humility. Therefore the essence of the essence is humility!

Therefore, Srila Krishna das Kaviraj Goswami said “One who thinks himself lower than the grass, who is more tolerant than a tree, and who does not expect personal honor yet is always prepared to give all respect to others can very easily always chant the holy name of the Lord. Raising my hands, I declare, Everyone please hear me! String this verse on the thread of the holy name and wear it on your neck for continuous remembrance.One must strictly follow the principles given by Lord Caitanya Mahāprabhu in this verse. If one simply follows in the footsteps of Lord Caitanya and the Gosvāmīs, certainly he will achieve the ultimate goal of life, the lotus feet of Śrī Kṛṣṇa.”  – CC Adi 17.31-33

As per my understanding. humility is as follows;

1. to be sincere, serious and no other ulterior motive but to follow the instructions of the spiritual master
2. to do one's best in fulfilling the mission of the spiritual master
3. to try one's best to depend on Krishna in all circumstances and pray to Him always
4. to internally cultivate a mood of service to all living beings and mood of love for Krishna

Hare Krishna