How Did Sahaba Use To Give Dawah To Non-Muslims?
There can be more than one way to introduce Islam to Non Muslims but the basic thing is that it must be based on Quran and the established history of prophets which is continuously coming from Bani Israel and Bani Ishamael. We cannot exceed Quran. That is why to preach Islam to Non Muslims is not the responsibility of ordinary Muslims. It is basically the responsibility of Bani Ishmael. ( See for details, The Law of Dawah, in Meezan by Ghamidi sahib). However if someone wants to do this noble job he or she needs to be well versed in Quran first.