If you want to preach the Bhagavad-Dharma, first you must be a bhagavat. You may have great taste for speaking and singing, but are you speaking and singing of Hari, or of Maya? Unless you are a Bhagavata yourself, your preaching is not Bhagavad-Dharma or Bhagavata-pracara, it is maya-dharma and maya-pracara.