In Baptism, each person becomes a child of God. They begin their life of grace in those cleansing waters. They begin their spiritual life through water and the Spirit.
To grow spiritually, the Christian must enter into a closer relationship with God. Baptism is only the beginning of the life of grace. After Baptism, the Christian is still an infant in the faith, regardless of age. Baptism is the first of the Sacraments of Initiation. Once a new Christian is made in Baptism, the Christian soul must be nourished. When the spirit is nourished, the person grows and thrives.
The greatest aids in spiritual growth are the seven Sacraments. The Christian continues their initiation into the faith through receiving Eucharist. They receive the Body and Blood of Christ as their food. Christian initiation is completed with Confirmation. In Confirmation, the Christian is sealed with the Holy Spirit. The sacrament of Reconciliation heals the wounds of sin. Anointing of the Sick gives healing to both the body and soul. Holy Matrimony allows those who are called to enter into communion with another person and raise up a Christian family. Finally, some men are called by God to Holy Orders to serve and lead the Church. Through the sacraments, the Christian grows in faith, from being an infant to a mature Christian.
After the sacraments, prayer is very important. Prayer is entering into union with God. We have been blessed by God with many ways of praying. There is mental prayer. There are vocal prayers. One can read the Bible. Others pray the Rosary. All of these are good ways of approaching the Lord. Prayer is essential for the spiritual life, no matter who you are.
Links to Some Spiritual Classics:
Abandonment to Divine Providence by Jean-Pierre de Caussade (d. 1751)
Ascent of Mount Carmel by Saint John of the Cross (1542-1591)
Conferences by John Cassian (360)-435)
Confessions by Saint Augustine (354-430)
Dark Night of the Soul by Saint John of the Cross (1542-1591)
Dialogue by Saint Catherine of Siena (1347-1380)
Imitation of Christ by Thomas a Kempis
Interior Castle by Saint Teresa of Avila
Introduction to the Devout Life by Saint Francis de Sales (1567-1622)
On Loving God by Saint Bernard of Clairvaux (1090-1153)
Spiritual Exercises by Saint Ignatius of Loyola (1491-1556)
Story of a Soul by Saint Therese of Lisieux (1873-1897)
Uniformity with God's Will by Saint Alphonsus de Liguori (1696-1787)
Way of Perfection by Saint Teresa of Avila (1515-1582)