One prepares to receive the Holy Spirit through prayer, rejection of sin and acceptance of Jesus Christ as Lord. In some Christian traditions, such as Roman Catholicism and certain strands of Orthodoxy, the Christian receives the Holy Spirit in a special way through the sacraments of Baptism and Confirmation.
Preparation to receive the Holy Spirit is more extensive and thorough in Christian churches that impart this gift through the sacraments of Baptism and Confirmation. In the case of infant baptism, the parents are the ones who prepare the child for the reception of the Holy Spirit, whereas in the case of adult baptism the individual being baptised prepares for this gift through prayer, penance and taking part in the Rite of Christian Initiation for Adults, or RCIA.
In Christian communities that have the Sacrament of Confirmation, preparation to receive the gifts of the Holy Spirit entails special religious instruction with a strong emphasis on the theology of the Holy Spirit, prayer and sacramental confession of mortal sins. The Roman Catholic Church considers reception of the Holy Spirit in the Sacrament of Confirmation without prior sacramental confession of mortal sins to be a grave offense against the dignity of this sacrament.