There aren't easy answers to this question or questions like this one.  In the simplest terms "vocation" means a "call".  So in general terms your vocation is what God calls you to do with your life.   Frederick Buechner author of Wishful Thinking:  A Seeker's ABC describes vocation as "The place God calls you to is the place where your deep gladness and the world’s deep hunger meet."
 

Here are some suggestions to help you find answers:

1. Pray and when you think you're done, then pray some more.  Talk to God and of course listen too.  Prayer is an essential element to life.  Create moments that may help you develop your relationship with God.   You may find links for prayer ideas here.
   
   
2. Find a spiritual director, mentor or guide.  Spiritual direction is the process of accompanying people on a spiritual journey. Spiritual direction exists in a context that emphasizes growing closer to God.  If you are interested in learning more about spiritual direction or would like a list of available directors in the Diocese of Buffalo, please contact Greg Coogan at gcoogan@buffalodiocese.org or 716-847-8789.
    
3. Get out there (in the community, in the parish, at school).  You are needed!  Think about engaging your faith in action.  Be involved in ways that give you life and help the world.  Activities like volunteering for Habitat for Humanity, local soup kitchens, food pantries, and nursing homes will help you to see the face of Christ in other people.  It will also put you in touch with others who like to serve.  Your parish community needs you too.  If you feel called to be in music ministry; to read at Mass or to volunteer with your parish's knitting ministry, identify yourself and engage as much as you can.  For more information about community service opportunities, feel free to contact Greg Coogan at gcoogan@buffalodiocese.org or check with your parish or campus community.
    
4. Test the "waters" - Engage in heart to heart conversations with the people who matter to you the most.  Your family and friends are a great sounding boards for career and vocational decisions.  Learn from others who know you.

Links on callings to the single life, married life, priesthood, or life as a consecrated religious sister, brother or priest may be found below:

Catholics on Call

Diocese of Buffalo Vocations Office

Vocation Network

Is the Single Life a Vocation?

Is marriage for us?