I've been reading "Don't Make Me Count To Three", a book about child training by Ginger Plowman. She discusses that you need to get the heart of the issue with your heart: why they are sinning, what God thinks of that sin.
One verse that she shares is Proverbs 20:5 which says, "A plan in the heart of a man is like deep water, but a man (or woman!) of understanding draws it out." The thoughts that are in our hearts, and even in the hearts of our young children, are very deep, and often connected to sin. When we understand, or help our children to understand, that they are sinning, are being selfish, prideful, etc. it is possible to change those sinful attitudes.
I read this and thought, I need to draw out what is in Eli's heart. But I must have understanding, and I often do not. James 1:5 is an encouragement though, it says, "If any of you lacks wisdom, let him ask of God who gives to all generously and without reproach, and it will be given to him."
The combination of these two verses have become my prayer in teaching and training Eli (and whatever other children Andy and I are blessed with!) in godliness.