Yeah just ask them about what they're interested in, then ask them why, what makes them passionate about that. What that originated from, tell them it's interesting, talk about how it relates to you, where possible. Exchange with them, the same insight into yourself - ideally, they ask for this from you too.
The only time you're going to have trouble with this type of conversation is when the person you're talking to is boring, because they don't have anything they're particularly interested in, or passionate about.
Even if I'm not explicitly interested in something I'm always interested in hearing about what other people are interested in. If it's their passion, then that makes it interesting. If they say, hypothetically, they're into writing music. You can ask so many questions about that. What got you into writing? What inspires you? Regardless of what they say, act impressed, tell them you're really interested. Tell them you've never met anyone doing that before if that's true, etc.
The thing is that women get compliments all of the time, but they rarely have men take a genuine interest, in their interests. Male and female interests often, fail to overlap too significant. Fuck, look at the differences in average info on OKC profiles (note, this is from 2010 so it's outdated, but stressed the same point).
It's not that many of those things aren't interesting to me, it's just that I don't know much about them. It's also about picking things they may be less secure about, and telling them that you find it interesting, or cool, so that they feel more comfortable with you. A girl the other week showed me some of the lyrics she was working on, for a song for her band - she said she wasn't very confident, I took the time to interpret the meaning, explain my interpretation to her and tell her I enjoyed reading it - she said it cheered her up that day. I'm not inherently interested in music, or soppy love lyrics, but it can be interesting, especially in conversation with the right person.
