Teaching your children how to pray can be a daunting task. The best place to start is with common prayers for children that can be easily memorized. Children who are making their First Communion should have memorized most of the following prayers, while the Grace Before Meals and the Guardian Angel Prayer are prayers that even very young children can learn by repeating them daily.
The Sign of the Cross is the most basic Catholic prayer, though we don't often think of it that way. We should teach our children to say it with reverence before and after their other prayers.
The most common problem that children have in learning the Sign of the Cross is using their left hand instead of their right; the second most common is touching their right shoulder before the left. While the latter is the correct way for Eastern Christians, both Catholic and Orthodox, to make the Sign of the Cross, Latin Rite Catholics make the Sign of the Cross by touching their left shoulder first.
We should pray the Our Father daily with our children. It's a good prayer to use as a short morning or evening prayer. Pay close attention to how your children pronounce the words; there are a lot of opportunities for misunderstandings and mispronunciations, such as "Howard be thy name."
Children naturally gravitate to the Virgin Mary, and learning the Hail Mary early makes it easier to foster devotion to Saint Mary and to introduce longer Marian prayers, such as the Rosary. One useful technique for teaching the Hail Mary is for you to recite the first part of the prayer (through "the fruit of thy womb, Jesus") and then have your children respond with the second part ("Holy Mary").
4. The Glory Be
The Glory Be is a very simple prayer that any child who can make the Sign of the Cross can easily memorize. If your child has trouble remembering which hand to use when making the Sign of the Cross (or which shoulder to touch first), you can get some extra practice in by making the Sign of the Cross while reciting the Glory Be, as Eastern Rite Catholics and Eastern Orthodox do.
Acts of Faith, Hope, and Charity are common morning prayers. If you help your children memorize these three prayers, they will always have a short form of morning prayer at their disposal for those days when they don't have time to pray a longer form of morning prayer.
An Act of Hope is a very good prayer for school-aged children. Encourage your children to memorize it so that they can pray the Act of Hope before taking a test. While there is no substitute for study, it is good for students to realize that they don't have to rely on their own strength alone.
Childhood is a time filled with deep emotions, and children often suffer real and perceived slights and injuries at the hands of friends and classmates. While the primary purpose of an Act of Charity is to express our love for God, this prayer is also a daily reminder to our children to try to develop forgiveness and love toward others.
The Act of Contrition is an essential prayer for the Sacrament of Confession, but we should also encourage our children to say it every evening before they go to sleep. Children who have made their First Confession should also make a quick examination of conscience before saying the Act of Contrition.
Instilling a sense of gratitude in our children can be especially hard in a world where many of us have an overabundance of goods. Grace Before Meals is a good way to remind them (and ourselves!) that everything we have comes ultimately from God. (Consider adding the Grace After Meals to your routine as well, to cultivate a sense of thanksgiving as well as to keep those who have died in our prayers.)
As with devotion to the Virgin Mary, children seem predisposed toward belief in their guardian angel. Cultivating that belief when they are young will help to protect them from skepticism later on. As children grow older, encourage them to supplement the Guardian Angel Prayer with more personal prayers to their guardian angel.