By devotion to one's own particular duty, everyone can attain perfection. Let me tell you how. By performing one's own work, one worships the Creator who dwells in every creature. Such worship brings that person to fulfillment.
The Japanese word "Ikigai" is similar to the English notion of avocation. Somewhere in-between a hobby and a purpose of life. The Germans have the word "Berufung" - one's calling - which is closely related to "Beruf", one's profession. That is, how nice would it be if ones calling could be one's profession as well.
Lord Krishna's notion of "dharma" sums the entire paragraph up in one word: it is the idiosyncratic mission in life each of us has. All of us have a special calling, a profession or vocation that allow us to make a name and a living for ourselves, while expressing our soul longing and being able to serve others at the same time. Find your own 'Ikigai": the place where mission, passion, profession and vocation come together. Do that which you love; that which you are good at; that which the world pays you for, and that which the world needs.
One note of caution though, there is a tendency in our spiritual community to look for self-expression and to only do what one finds spiritually fulfilling. Going after your dreams is certainly your birthright, but please be mindful of the fact that the Bhagavad Gita's emphasis is on self-less service. Sometimes it is simply not about us, but about the people we serve. I would recommend patience along the WAY. If material needs force you to do something that you feel ambivalent about right now, maybe there is spiritual meaning in that situation as well.
Your opportunity to express your passion will come; find that open door when the opportunity presents itself.
What's your mission in life?