How can a person be a means for someone's guidance to Islam, and is there a transmitted method from the Prophet Muhammad, may Allah's peace and blessings be upon him, to achieve that?

Working for the religion is the responsibility of every Muslim, and whoever turns away, Allah will replace him with another. Among the greatest things that help influence others are: pride in Islam, making it a constant concern, and steadfastness and adherence to the religion outwardly and inwardly. Al-Shafi'i said: "He who admonishes his brother by his action is a guide." The method of the Prophet, peace and blessings be upon him, in da'wah differed according to the invitees and the condition of the Muslims. One can benefit from books of seerah (definition) and shamail, especially the part on seerah from "Zad al-Ma'ad fi Haday Khair al-'Ibad" by Ibn al-Qayyim. There are books that sharpen resolve and enlighten one about the means and methods of da'wah, such as: "Qabasat min al-Rasul" by Muhammad Qutb, and "Al-Muntalaq," "Al-'Awa'iq," and "Al-Raqa'iq" by Muhammad Ahmad al-Rashid, and "Mushkilat al-Da'wah wal-Da'iyah" by Fathi Yakan, and "Usul al-Da'wah" by Abd al-Karim Zidan.