Psychotherapists have a simple way of figuring out how to apply talents and abilities in life for the sake of serving others. You need to ask 4 questions:

What do you like? Write a list
What can you do? List
What do they pay for? List
What do people need? List

There must be at least one coincidence - this is your God's purpose.
Passion is the coincidence of the first two.
The second and third - career.
The first and last is a mission.
The last two are vocations.