To enter into Krishna Leela, it is binding on a devotee to take the route of Gaura Leela because this is the only way that one will understand the mood of Sri Krishna and the associates of Krishna in Krishna Leela.
As one enters Gaura Leela, one needs to understand the governing principles of Bhakti. The major tattva (principles) to be looked are Sadhaka Tattva, represented by the Six Goswamis of Vrindavana, The Sadhaka Bhumi, represented by Nabadwipa Dhama, The Seva Prapti Bhumi, represented by Sri Vrindavana Dhama, The Jugala Tattva (The principle of Divine couple) represented by Sriman Chaitanya Mahaprabhu and the Guru Tattva represented by Sri Nityananda Prabhu. The path towards the divine couple can be only approached by first seeking the mercy of Sri Nityananda Prabhu, then through Him getting the mercy of Sriman Mahaprabhu and in that order finally getting the mercy of the Divine Couple Sri Sri Radha Govinda. This is the bonafide system of attaining eternal service in the spiritual realm of Goloka.
It is interesting to see an anecdote from Srila Raghunatha Dasa Goswami’s life in connection with the Nityananda Tattva. Right from childhood, although Dasa Goswami was from a very affluent family, his intentions were very clear and that is to surrender to the Lotus feet of Sriman Mahaprabhu. During those early years of his life although, Dasa Goswami had attempted twice to offer himself to Sriman Mahaprabhu, Sriman Mahaprabhu sent him back saying that he should wait for sometime before dedicating his life to Sriman Mahaprabhu. On a third occasion Dasa Goswami arrived at the place where Sriman Mahaprabhu was put up. Interestingly this time Sri Nityananda Prabhu was present at the meeting place and He greeted Dasa Goswami. He told Dasa Goswami “I have heard that you want to attain the mercy of Sriman Mahaprabhu. But you see, you are a thief, you have tried to steal my property without my permission, unless you get my permission you shall not attain the mercy of my Lord Gaura”. Dasa Goswami immediately asked for forgiveness and having offered Dandavats (prostrated obeisance) to Sri Nityananda Prabhu, the kind Lord placed both His feet on Dasa Goswami’s head and permitted Dasa Goswami into the inner fold of Sriman Mahaprabhu’s associates. As a follow-up of this Leela, Dasa Goswami conducted a huge “Bhandara” (feast) in the village. It is only after this leela that Dasa Goswami was fully accepted by Sriman Mahaprabhu.
The above anecdote illustrates that unless one fully surrenders to Nityananda tattva, none will actually obtain the mercy of Sri Gauranga in totality. Sri Nityananda Prabhu is the representation of the “Samasti” Guru; the highest representation of the Guru Tattva, the totality of the Guru principle. The principle of the Lord can only thus be approached through the Samasti Guru, the universal Guru. The physical representation of the Samasti Guru is the Vyasti Guru (the Sadhguru) who comes in front of the aspirant both as Shiksha Guru and Deeksha Guru. It is important for a practising Gaudiya Vaishnava to invoke Sri Nityananda’s mercy into one’s life, for success in Bhakti.
The practical methodology of invoking Sri Nityananda’s mercy for a sadhaka is to read about Sri Nityananda Prabhu from books like Nityananda Charitamrita by Vrindavana Das Thakura, Chant His holy names, remember the various symbols on His footprints, Singing Gaudiya Geeti which describes the qualities and mood of Sri Nityananda Prabhu. One also renders service to Sri Nityananda Prabhu by serving Sri Gurudeva.