Your personal relationship with Jesus is the heart of any vocation you have from him. It is above all in your prayer that you will hear his voice and know the spiritual calm that comes from discovering his will of love for you.
Deepen your prayer-life as you test your vocation. Try different kinds of prayer, read books on prayer, join other people in prayer. The Divine Office, the Prayer of the Church, will be an important part of your ministry if you become a priest: perhaps begin now to pray part of it each day (e.g. Morning and Evening Prayer).
Ask God to show you what he wants of you, and to guide those who are there to help you and to discern your vocation. Ask others to pray for you. Become more and more a man of prayer.
Make the Eucharist central to your life. Sunday Mass should be the climax of your week, but it may be possible for you to go to Mass on other days as well. Grow to love the Eucharist, spend time in adoration of the Blessed Sacrament and become a truly Eucharistic person.