My first venture outside of corporate, I decided to do something within the realm of that same industry, it felt familiar and I knew parts of the market and how the idea could work. I mistook this at first for passion, although it was a niche and the opportunity I identified within that industry seemed promising, it wasn't a passion. A few years later after the initial drive had burned up and the realization came to me that I was never really passionate about the industry, I decided to exit. Reflecting upon that and it has been a few years since being engaged in various passion projects and ventures, I can clearly see the difference in the initial project and the latter.
The initial project seemed familiar and comfortable, which made me believe that this was my domain of expertise. I have come to realize my expertise could be applied to other industries and it was just that I was comfortable within that familiar industry that I mistook the industry for my passion for the work I was doing, whereas in reality, my passion was in the work itself.
Reflecting upon this question, I believe that passion is something that you come across when you have experienced enough to realize it and to hone any talent in life is through practice. Experiential learning and practice is probably the best way to become successful at your own marketable talent. This reflects in both your own personal growth but also professional growth, the more you engage in your skillset and expose yourself to the market, the more you build in your own confidence of it but also your own network/referrals within that domain of expertise grow.