"Srimad-Bhagavatam" gives us Krisna Himself, not a conception or theory of Krisna. Krisna becomes a prisoner of our heart, if we are eager to hear about Him, and do it with a proper mood.
The progress in bhakti does not depend on our own endeavor, it depends on the mercy of the Lord. Path of bhakti is completely causeless. And the seventh canto of "Srimad-Bhagavatam" tells us what we are supposed to do to increase this chance to get causeless mercy of Krisna.
We are supposed to develop a very strong desire to become pure devotees, because it will solve all our problems. While reading the sixth Canto a very strong desire to get pure devotion should arise in our heart, and the seventh Canto describes two ways how to get it and how to develop a certain nature, which is favorable to bhakti.
On very rare occasions bhakti is coming from the Supreme Lord, in most of the cases bhakti is coming from the heart of a pure devotee. And for that you have to please the pure devotee, you have to enter into some personal relationship with him. Bhakti comes by the submissive hearing and service attitude. We will never be able to get rid of attachment to sense gratification on our own until we open our heart to a pure devotee, listen to him and try to serve him.