Helping your kids learn to share their faith begins in one easy step: they watch you share your faith. Whether it is watching you invite friends to church or asking your friends about a prayer request, kids pick up on the idea that it is "normal" to do these things. How do you make it a normal part of your life?
1) Identify people around you who are hurting, not in church, or disenfranchised with the church. Who are those folks you come in contact with on a regular basis that simply are not following Christ? It's not an accident that you keep bumping into them.
2) Intercede for those people you have identified. Pray for their family. Pray for their schedule. Pray for opportunities to invite them over to show hospitality or to invite them to church. Pray they would come to know Christ better.
3) Invest in them. Find out what their favorite soft drink or candy bar. Be intentional in running into them on a regular basis for conversations. Ask them how you can pray for them.
4) Invite them. Ask them over for a cookout with other families from your church. Invite them to church activities like swim parties and kids activities that their kids would have a blast at. Invite them to worship with you. Tell them, "let me come pick you up at such and such time for this event."
As you do this, include your kids in the discussion and the prayer times. As you do this, you will impact your family, your church, your community, and your world.