We all know someone whom we wish would convert to our beautiful faith. I pray for certain family members, and many of my friends. I'm sure I should pray for many more, individually, but I usually wrap it into one when I pray the rosary when I say "for the conversion of sinners throughout the world" in my intentions. There is a prayer to St. Joseph that I particularly love, from the book: My favorite Prayers and Novenas, published by Pauline Books and Media. So here it is for you.
Prayer to Obtain a Conversion
O holy St. Joseph, who merited to be called just by the Holy Spirit, I urgently recommend to you the coversion of (N.), whom Jesus redeemed at the price of His precious blood. You know how sad is the state and how unhappy the lives of those who have banished this loving Savior from their hearts, and how greatly they are exposed to the danger of losing Him eternally. I beg you not to permit a person so dear to me to live far from God. Preserve him/her from all danger. Touch the heart of this prodigal and lead him/her back to God. Do not abandon (N.) until you have opened to him/her the gates of the heavenly city, where he/she will praise and bless you throughout eternity for the graces owed to your powerful intersession. Amen.
I am, like my patron Saint, Teresa of Avila, devoted to St. Joseph, and find myself praying to him more and more- along with Mary!