Some wisdom from Tim Keller:
First, in sharing our faith, we take an intelligent approach, not an authoritarian one. We remember what it is like not to believe, and we do not expect people to believe simply by being told what is true. People want to know why.
Second, we take a “process” approach, not a “crisis” one. We provide multiple exposures to the gospel. We afford people the opportunity to ask questions, so that they receive information about Christianity in an order and shape that addresses their situation.
Third, we take a “presuppositional” approach to persuading people about the faith. That means we believe every person, even the skeptic, already does believe in God (Rom. 1:18–25). So we find “clues of God”—insights into truth—they already have, and use these to show the way back to their Creator. Jesus responded positively to a man who was in “process,” who said: “I believe; help my unbelief!” (Mark 9:24). We should want to do the same.