1. Be receptive
It is important to be attentive: you must take time to stop, reflect, and pray. To be open to God's will in your life you must be open to the signs God gives you. You must adopt an attitude that is receptive and confident. God provides the signs and seeing a spiritual director along with attending vocation events can help you identify them.
2. Pay attention to the events in your life
In order to discern these signs, and to discover God acting in your life, you must be vigilant in preparing your heart for the service of God's kingdom. God gives you parents, friends, the experiences of your life, and, at times, even suffering. All of these can prepare you for your future: the talents, interests and skills you acquire, and the educational and social activities you pursue.
3. Come to know
"Which of you wishing to construct a tower does not first sit down and calculate the cost to see if there is enough for its completion?" (Jesus, in Luke 14:28) Take the time to listen to your heart before pursuing something that may not really be all that helpful. Self-knowledge comes from experiencing different things but don’t spread yourself too thinly or always overload your senses. Be sincere and honest with yourself, and you will proceed confidently in all you do. Little by little, in making choices, you will make decisions that are in line with the course intended for you. What you want is important, but there is more as well! Know your capacities and limits; this is of primary importance in discerning your vocation.
(from the Franciscan Friars Province of Canada, 2006)