My church is small. Due to its size, if it was thing we have trouble with it is finding a youth pastor who understands, and lives according to the Bible (at least as much as possible). What I find is that children raised in Christian homes are familiar with God, Jesus, the Holy Spirit and the Bible. However, children being brought to the church for the first time in their pre-teen years seem to struggle with it.
What is your approach to teach children about God, the Holy Spirit, and Jesus? What mechanisms do you use to teach kids this information?