"Do not conform yourselves to this age but be transformed by the renewal of your mind, that you may discern what is the will of God, what is good and pleasing and perfect." - Romans 12:2
Discernment is listening to God and making decisions based on what you hear from him. Jesus says through out all four gospels, "be not afraid; come follow me!" In order to follow him, we need to listen to his voice. Prayer is the key to all of this discernment. Praying with scripture, the rosary, adoring the Blessed Sacrament are just a few ideas on how to pray.
Keeping yourself in constant contact with the sacraments helps in discernment. Going to Mass on a regular basis even during the weekdays, will help to hear God's voice. Going to confession on a regular basis, at least once a month, can help keep the Holy Spirit in your heart and guide you.
Finding a Spiritual Director can help you to see God's will more clearly. The first purpose of the spiritual director is to help a man construct a spiritual plan of life and hold him accountable to it. Then, once he is praying faithfully, using the sacraments, and growing in virtue, the discernment of one's vocation becomes a regular topic of discussion. The spiritual director also will guide the man to good books or resources to aid his discernment.
Bishop Robert Barron, former rector of St. Mary of the Lake/Mundelein Seminary near Chicago, shares some thoughts on discerning a vocation to the priesthood.
For more information on discernment, contact Father Joe Pins