Once God has predestined someone to be his child, the next thing to happen is something known as the effective call, in which an individual upon hearing the proclamation of the gospel responds in saving faith.
Behind the scenes, God the Father is drawing someone to himself to be in the family of God, and this is done through the preached word by a friend, family member or pastor. The theological term for this is effective calling, because when God calls someone from darkness into light, they cannot help but be overcome with joy and respond in saving faith.
The best explanation of this doctrine that I have heard is from pastor John Piper. He said effective calling is likened to someone taking a nap on their couch (a metaphor for being dead in their sins and not believing in Christ), and a friend coming up and yelling WAKE UP!! (a metaphor for God’s calling to become a Christian). Really the only response you have is to jolt awake and respond.
This is why it is so important to talk about Jesus with those you have a relationship with. Romans 10.14 says, “How then will they call on him in whom they have not believed? And how are they to believe in him of whom they have never heard? And how are they to hear without someone preaching?" The only way for those who are not Christians to have eternal life is for another person to tell them about Jesus and for that person to believe.
If you are a Christian, think about 3 people who you have a friendship with and can be praying for and talking to about Jesus at the appropriate time. And if you are not a Christian, pray and ask God to make himself known to you in a real, tangible way this week.