The Shepherd's Fellowship blog has a great article detailing how we ought to evangelize our children.
The process of evangelizing one’s children, however, can be a daunting task. For many parents, the questions are as practical as they are disconcerting: How should I present the gospel to my children? What’s the best approach to take? How do I know if I’m doing it right?
Pitfalls, both real and imagined, intimidate virtually every parent who contemplates this responsibility. On one hand, there’s the danger of leading children to think they are saved when they are not. On the other, there’s the risk of discouraging children who express a genuine desire to follow Christ.
How, then, should we evangelize our children?
The elders of Grace Community Church began to answer this question by noting what child evangelism should NOT be... that list includes
1. Oversimplifying the Gospel of Christ
2. Coercing a Profession of Faith
3. Assuming the Reality of Regeneration
4. Assuring the Child of Salvation
5. Rushing the Ordinance of Baptism
Everyone should read the whole article since the application extends beyond our own families into the life of the church and our evangelism of adults.