The primary role of the altar server is to assist the priest in the celebration of the liturgy during Mass. This is done through specific actions and by setting an example to the congregation by active participation in the liturgy (hymns, responses, etc.), by looking alert and sitting or standing at the appropriate times.
Servers carry the cross, hold the book for the priest celebrant when he is not at the altar, carry the incense and censer, present the bread, wine, and water to the priest during the preparation of the gifts or assist him when he receives the gifts from the people, help the priest wash his hands and otherwise assist the priest celebrant and deacon as necessary.
Loving Father, Creator of the universe, You call Your people to worship, to be with You and each other at Mass. Help me, for You have called me also. Keep me prayerful and alert. Help me to help others in prayer. Thank you for the trust You've placed in me. Keep me true to that trust. I make my prayer in Jesus' name, who is with us in the Holy Spirit. Amen.