People should not pray to Mary or to any of the Patron Saints. The teaching of Scripture and of the Savior is that we are to pray to the Father through the Son (our one and only mediator) in the power of the Holy Spirit. Compare the following passages (John 14:13; 51:16; 16:23-24; Eph. 1:17; 3:14; Col. 1:3; Eph. 6:18; Jude 20).
The idea of praying to her is completely contrary to the Bible since prayer is to be expressed to God only—specifically, to the Father, in the name of the Son, and in the power of the Spirit.