Q. “How can we effectively witness to those who don’t believe in the Bible?”
A. It’s important to keep in mind that you cannot persuade someone into being a Christian. That is the work of the Holy Spirit over time. And that revelation usually does not come through debate, though those conversations are a means by which the Spirit may work in their heart and mind.
People need time and truth. Peter tells us to be ready to give an account of the hope that is within us with gentleness and respect (1 Peter 3:15).
So in a nutshell, that’s our job—to be available. God is not pressuring you to win every argument. You don’t need a foolproof plan to prove that the Bible is true. Your best witness is to brag on Jesus and the benefits of knowing Him.