Before plunging into a spiritual conversation, it is important to build a relationship, even if that means talking to them for a few minutes on topics they’re interested in before you turn the topic of Jesus.
First introduce yourself, especially if it’s a total stranger, and then ask them if they would be willing to talk about spiritual matters. If they say yes, then it’s time to start sharing the Gospel! If they say no, don’t take it personal. Like God told Samuel, “They have not rejected you, but they have rejected me.” (see 1 Samuel 8:7).
Pray for them in your heart whenever you part ways and stay encouraged.
“But in your hearts revere Christ as Lord. Always be prepared to give an answer to everyone who asks you to give the reason for the hope that you have. But do this with gentleness and respect, keeping a clear conscience, so that those who speak maliciously against your good behavior in Christ may be ashamed of their slander.” –1 Peter 3:15-16 (NIV).