Finding activities, pastimes, and even people that I'm actually what I'd call passionate about has never really been something that's come easily to me. This has especially been the case when it comes to anything long-term or potentially permanent. I was the type of kid that never really had a real answer for the adults in my life when they asked me what I wanted to be when I grew up. I always had a hard time connecting with other people as well.
That said, I'm not so sure that I actively find passions so much as they find me. Most of the things I'm voraciously interested in I embraced in the first place because they made me feel calm and at peace, as opposed to because they lit some sort of fire inside of me. They were ways for me to form a buffer between myself and the rest of this world that made me feel so rejected early on in my life. The feelings of passion toward those beliefs and pursuits came later on after I'd developed the associated skills almost by accident thanks to repetition over the years.
These days, I typically stumble across new things to be passionate about through reading. I love to read about anything and everything -- news, religion, food, culture, history, travel. I'll read about something in a magazine or in a novel, become intellectually curious about whatever it is, and seek out more information about it. After a while, it starts to get into my head and before I know it, I've found a new passion that I fervently believe in. That's how a lot of my most recent passions began -- like Catholicism and buying/eating local produce.
It's honestly very rare for another person to turn me onto something new -- especially anything that's about a lifestyle change. I'm sure that's why things like career suggestions from my parents and teachers were never really taken to heart. It has to be something I choose to get into on my own or it just won't stick.