What are the conditions for the success of the Da'wah?

Among the conditions for the success of daʿwah (calling to Allah) are: learning the Islamic sciences, knowing the state of those being called, familiarizing oneself with the methods of daʿwah, progressing from the more important to the important, using wisdom and good admonition, being gentle, avoiding harshness, considering the time and place, being patient and tolerant, and ensuring that the daʿī's (caller's) conduct and actions align with what he calls to.