Preaching Krishna Consciousness means simply to convert people from envy to non-envy towards God-Krishna.
This envy towards God-Krishna takes so many shapes and forms such as
1.completely denying the existence of God (atheism)
2.doubting the power and energy of God (skeptics)
3.accepting other smaller powerful entities (demigods) as the Lord of the heart
4.accepting one’s own (material) abilities/inabilities as the absolute reality (thus creating modern science and scientists)
5.accepting an all powerful God for one’s own pleasure (thus creating variety of religious and sub-religious principles).
6.finally…concluding that “I am God”
This envy that we have takes so many forms depending on one’s consciousness. Therefore, preaching is to provide medicine to this envy. How…by explaining in a nice way our own short comings and presenting a blissful alternative that is associating with God. This is not easy especially if we have really short periods of interaction with people.
Trying to convince people and to be convinced ourselves that we cannot enjoy in this material world but rather God is the Supreme enjoyer is the biggest obstacle, for one who is convinced of this truth, will gradually take to the process of pure unalloyed devotional service. Till then it will be either no devotion or mixed devotion.