There are several authors like Fernando Corominas in Spain, that claim that when we are children, there are different ages when we will absorb different skills easier than others; these are called "sensitive periods" for learning.
For example: It is much easier for a 1 to 4 year old toddler to learn a new language, than for a 30 year old adult. It does not mean the older person cannot do it, it means that it is much easier for a 1 to 4 year old to do it because his or her brain is specially "wired" at that age to learn languages. This is great news because if we know when they can absorb each type of information the best, we can then proceed to teach our children different virtues and abilities at different ages when they are most likely to learn them naturally and easily!
From 0 to 4 years old: The focus should be in teaching order, obedience and truthfulness - Imagine how much time and effort we can save teaching these virtues at this age, rather than later in life! Also, this age is great for teaching balance and introducing our kids to languages and music. We have seen it with our kids: we have been able to teach them to ride their bikes without training wheels (balance!) in half the time when they are four years old, than when they are older - its really noticeable.
From 5 to 7 years old: playing skills, following rules, team work. It is fun to see how well they can understand the rules and make everybody else follow them.
From 7 to 11 years old: fortitude, charity, perseverance, laboriousness, patience, responsibility, justice, generosity. They love to talk, they want to participate. They are in elementary school, they have homework to do, they are eager to do it and we listen to the famous "it's not fair...".
From 13 to 15 years old: temperance, faith, intimacy, sobriety, friendship, respect. They will choose who are going to be their friend to go through adolescence together, so watch out, guide them, and try to have a very friendly house, were your children's friends can stay close and SUPERVISED BY YOU. This is no good time to delegate this on others.
From 16 to 18 years old: prudence, hope, comprehension, loyalty, humility, optimism. They start to use their freedom, they begin to drive cars, so it is the right moment to teach them what it means, to tell them that we have built a trust with them so they shouldn't let us or God down. They will listen.
Children have, in their nature, the inclination to be good. They really want their parents to be proud of them, so they try to be good.
When we had our first daughter it was very easy to put in practice these ideas, but now that we have five children, of different ages, it is very hard to keep track of it all. We try to focus on the very important things and give them very small amounts of information at a time. The good thing is that the older ones help a lot. Having the older brothers and sisters setting the good example for the younger ones is one hundred times more effective than having hours upon hours of talks. So now we are harvesting what we planted. And supervising.
It is not easy at all. Don't think that because I write this, my family is always perfect. I write this, because more often that not, we are in a complete chaos, but we have tried different tools to reorganize ourselves and get back on track and I try to transmit to you through this blog what has and has not worked.
Have fun enjoying every stage in your children's lives!