A good way to focus is by evaluating objectively what skills/advantages are you bringing to the table that give you the edge. Sometimes evaluating that capabilities against what you're passionate about helps as well. People tend to perform better doing something that they love rather than something they should.

To find that 1 thing, it is like found the girl you like. You will just know. If you still haven’t found it yet, force marriage concept works too. Choose one and dedicate your time to do it and over the time you will learn to love it and that thing will be the one.