According to Deut 6:5-7, there are only two basic ingredients needed to be a God-ly influence on your child: 1) Be godly yourself, and 2) Teach your child to be godly.
First, be godly yourself.
You shall love the LORD your God with all your heart and with all your soul and with all your might. And these words that I command you today shall be on your heart.Deuteronomy 6:5-6 (ESV)
Love God with all your heart, soul and mind, and let His Words always be in your mind. Simply put, you will be godly yourself if you Love God, and Know His Word.
In other words, to prepare (or repair, if you have already been on the parenting road for a while) best for parenthood, work at making the most distinguishing aspect of your relationship with God your love of Him. To do that you will need knowledge of what love for God is, namely knowledge of His commandments. Only with a solid and presentable understanding of Who God is and how He works will your love for God be clearly identifiable by yourself, others, and especially your children.
Love God first and foremost, above all else. Get excited about talking to God in private and talking about God in public—specifically when you are with your family. Make much of God in your thoughts, convictions, and conscience. Read God’s Word with eagerness, joy, and purpose. Study to have a clear understanding and knowledge of what the Bible says. Build a list of convictions from Scripture that you will live by, and make them the boundaries for your family. Determine from Scripture what you will involve yourself and your family in, and what you will protect yourself and your family from.
Then, teach the godliness you are aiming for, to your children. Be godly yourself and also teach your children to be godly. Learn the basic Christian skill of being able to study God’s Word accurately, allow it to impact your life deeply, and then formulate a clear way of teaching that new-found knowledge to your family. Be an expert at teaching your family what God had taught you.
You shall teach them diligently to your children, and shall talk of them when you sit in your house, and when you walk by the way, and when you lie down, and when you rise.Deuteronomy 6:7 (ESV)
To be a parent is to be a teacher. To be a parent is to study the skill of speaking in such a way that you are worth being listened to. Have something worth saying, and learn to say it in a helpful way.
Reading the book of Isaiah to your five year old might be over his head a little, but teaching from Isaiah that God is Holy and works to make people like us holy is useful to a five year old (and fifty year old!) coming to grips with sin realisation.
As a parent you are to have the very words of God on your heart. Read your Bible, know your Bible. Then teach your children what you have come to know. Teach it diligently to them so that, from a young age already, their knowledge of God and of the Word will excel even their ability to read. Then, as they grow up to read the Scriptures themselves, they too will be able to form their own convictions of being godly and they too will be able to formulate helpful ways of teaching it to others—Lord willing, their own families one day.
If you will be good parent, then be godly yourself by loving the Lord and knowing His Word. Teach your children to be godly by teaching them about the Lord you have come to know and love.