I don't try to talk people out of what they want to believe. I stick with quoting scriptures in context (e.g. John 14:6) and let The Word and Holy Spirit do the work I could never accomplish - water and grow the seed of God's truth.
I stick with quoting scriptures...Can you imagine a Bible that covered "everything" important to the Christian faith? It would be ten miles high and then some. http://www.catholic.com/tracts/scripture-and-tradition