That's a good question. No magic bullets, but I think one principle is to keep it casual. A lot of journalists get so into the mindset of shaping a character in their heads that they forget to experience whatever it is they're doing.
E.g. When someone is walking through the buffet in a diner, that's probably not the time to ask, "How old are you? How long have you lived here?" Better to say "These yams look delicious" and see where the conversation leads.
