Preaching means to see whatever little spark of bhakti in someone and fan it into a blazing fire, which will burn all the anarthas (contaminations) and make him a great devotee.
Books are the basis of our Movement. Without our books, our preaching will have no effect.
Preaching means to spread the glories of the Supreme Lord.
Simply read my books and repeat what I have written then your preaching will be perfect.
Preching means book distribution.