The fact of salvation means nothing unless a person accepts it for himself or herself. Emphasize that even if the person grew up in church, he or she still needs to accept Jesus personally. Also emphasize that even if the person has led a terrible life, no one is too bad for God--a person does not have to clean up his act before coming to Christ. In fact, Jesus died to take away all that sin and to help the person start anew. So emphasize that being good is not good enough, yet no one is too bad to be able to be forgiven--God wants all people to come to him. All people need to trust in Jesus in order to be saved. So what kind of response should a person have? Talk about the following:

You respond with belief in Christ.

Romans 10:9-10
If you confess with your mouth that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved. For it is by believing in your heart that you are made right with God, and it is by confessing with your mouth that you are saved.

You simply need to believe. That doesn't mean that you don't have any questions or that you understand everything. It simply means recognizing that you are indeed a sinner in need of a Savior. You recognize that you cannot be good enough for a perfect God on your own. And you understand that God loved you so much that he sent Jesus to save you. If you believe that, say so.

You respond by receiving Christ.

John 1:12
But to all who believed him and accepted him, he gave the right to become children of God.

Receiving Christ means acknowledging your belief in Christ, inviting him to come into your life, turning to God from your present way of living (repentance), and then beginning the adventure of letting God direct your life! And the moment you ask, it's done. Jesus has come in!