A big problem is many people have become lazy. Many faithfully follow denominational teachings, or rely on other's opinions rather than searching out what God has to say on a subject.
Jesus said it is those who hunger and thirst after righteousness that will be filled; meaning those who wish to be filled must be willing to search the word. (Matt. 5:6, 2 Tim. 3:16) And Jude actually gave instructions concerning where to look for the common salvation. He strongly urged people to search out what was first delivered to the apostles. (Jude 3) This points directly to the gospel message initially presented in Jerusalem on the Day of Pentecost. (Acts 2, 33, 36-42) It was on that day that the NT rebirth via water and Spirit became possible for people. The same message was then carried forth to many others. (Acts 8, 10, 19, 22, etc) After being reborn it is the indwelling presence of God's Holy Spirit that guides people into all truth: "Howbeit when he, the Spirit of truth, is come, he will guide you into all truth: for he shall not speak of himself; but whatsoever he shall hear, that shall he speak: and he will shew you things to come. " (John 16:13)
Another key in establishing whether a belief is accurate is that the biblical concept will be confirmed by 2-3 scriptures. For the Word says so: “…at the mouth of two witnesses, or at the mouth of three witnesses, shall the matter be established.” (Deut 19:15, 2 Cor. 13:1, Matt 18:16) An example: water baptism is to be administered in the name of Jesus. As all detailed accounts reveal, it is the only way NT baptism was administered. (Acts 2:38, 8:12-18, 10:43-48, 19:1-7, 22:16)