What is the methodology of calling to Allah, its principles, and its methods?

This is a very important topic, and a brief fatwa is not sufficient for it. One should reflect on the stories of the prophets and the Prophet's biography, and read books written on da'wah (inviting to Islam), such as: "Usul al-Da'wah" by Dr. Abd al-Karim Zidan, and "Al-Da'wah ila Allah" by Dr. Abu al-Fath al-Bayanouni, as well as the chapter related to enjoining good and forbidding evil in "Al-Ihya".