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.
Preaching means to awaken the real inclination to serve Krishna.
It is most difficult to preach to those who think they are spiritually advanced.
Krishna takes a special appreciation for His devotees who are engaged in risking for His preaching work and He will give you special care and guidance at all times because you are sincerely trying to serve Him in this way.
Philosophy is theP highest, but even higher than philosophy is the practice of philosophy. So if you simply remain pure, your preaching will have effect.
Preaching is more important than managing. Just because you are preaching nicely and distributing so much Prasadam, the management will follow like a shadow and Krishna will send you unlimited help.