One example from the book really grabbed me as we have a 4 year old struggling in this same area.
You want your children to develop the habit of prayer during times of temptation. Imagine a four-year-old who becomes angry with siblings over every offense, real or imagined. You want to accomplish more than adjudicating the conflict of the day. You want him to turn to God in prayer when he is tempted to be angry.
Have this converstion with him in the morning.
"Today you may be tempted to be angry with your sister. When you are tempted, I want you to come to Mommy and I will help you pray to God for grace. God can help you when you are tempted to be angry."
If your young child can learn to come to you to lead him to the throne of grace to find mercy and help in his time of need (Heb. 4:16), he will learn how to go there himself in the years to come.
Today, I applied this in our home. Strife was seeming to reign amongst our brown-eyed girls, so instead of reacting all frustrated and berating my kids with their errors, I gathered them together and prayed over them. I told God that we needed His help today to be kind and patient as it seems to be harder to do today. We do not want to be angry and impatient with each other, but we are a family that wants to show love to each other. Refocusing with prayer with them really helped to stifle the rivalry and brought unity into our home and reinforced the idea that we need God's help to change our behavior. It also proved to be a quick reminder when that impatience wanted to rise again by just saying, "Remember that we want to show kindness to each other." And they replied, "Oh, yeah."
This is just one tidbit that I learned from Instructing a Child's Heart. It will definitely be one that I will recommend to others.