How do I know what God is calling me to do?

You must pray every single day, asking God to reveal His plan for you. Do not ask yourself, "What do I want to do with my life?" This is the wrong question! Rather, you should be thinking and asking: "Jesus, what do You want me to do?" And listen for the answer!

The primary locus of revelation is the heart. Listen with your heart! The discernment process in the priesthood must also include the Church.

The local bishop is the one who ultimately decides who is and who is not called. He is assisted in this by the vocation office and the seminary. This process is called "discerning one's vocation."