When we don’t really know what we should pray for, St. Alphonsus instructs, we can simply ask Mary to pray for whatever she knows to be best for us:
Pray for me, Mary, and entrust me to your Son. You know my miseries and my needs far better than I do. What more can I say? Have pity on me. I’m so miserable and ignorant that I don’t know, nor can I even seek for, the graces that I stand the most in need of. My most sweet Queen and Mother, seek and obtain for me from your Son those graces that you know to be the most expedient and necessary for my soul. I abandon myself entirely into your hands, and I beg the divine Majesty only that, by the merits of my Savior Jesus, he will grant me the graces that you ask from him for me. Ask, ask, then, most holy Virgin, whatever you see to be best for me. Your prayers are never rejected. They are the prayers of a mother addressed to a Son who loves you, his mother, so much, and who rejoices in doing all that you desire. For he wishes to honor you more, and at the same time to show you the great love he bears you. Let’s make an agreement, then, my Lady, that while I live confiding in you, you on your part will concern yourself with my salvation.
—St. Alphonsus Liguori, The Glories of Mary