For children, believing and trusting is natural. However, parents and those who somehow deal with their spiritual education can promote that childlike faith to make it firmer.
Learn how to help them according to their age to wake up and develop that great force that will accompany them throughout their lives:
Between 0 and 3 years old:
Feeling loved as soon as possible and even during pregnancy will allow the child to experience that God exists and loves him.
Being taken care of in your basic needs (food, hygiene, sleep), protected from danger and listened to and watched with affection will record in your subconscious a sense of security that will serve you a lifetime.
From the earliest possible time, the little one should feel God in the life of his parents. At this stage, the religious experience must be transmitted within the utmost clarity and with concrete acts in a climate of intense affectivity.
Between 3 and 6 years old:
At this age you can help the child to dialogue with God simply and spontaneously, encouraging him to speak with confidence about his needs and desires. You can also teach simple prayers and present the Bible.
Any occasion is good to thank, but you can take advantage of moments of the day such as meals, waking up and going to bed, passing an ambulance or passing through a church so that the child consciously contacts him and speaks to him.
Little by little, the child is acquiring knowledge, also in the religious. Enter the stories of saints. There are many books and audiovisual resources that can help you.
Between 6 and 10 years old
This is the age of reasoning. Consolidate your religious formation by adapting your explanations, celebrations, and prayers to your age.
Respond simply and clearly to your questions about God, transcendence, life after death, the sense of suffering, and so on. As you know, listening to him and dialoguing with interest.
Take care of the people with whom you interact. Keep in mind the character of the school you choose for him and point him to catechesis or some training group with children his age.
Catholic children often celebrate their First Communion at this age. It can be a unique experience that you remember all your life.
Between 10 and 12 years old:
This stage continues along the lines of the previous stage, but with a clear orientation to prepare for the age of the crisis: adolescence. It is important to take care of your friendships and activities and help you use your freedom responsibly.
Offer clear criteria and make sure you have understood them well. Help him to live the virtues, especially the charity and the sincerity.