I found this 2003 article about Alec Soth and his process very interesting. The reporter follows Soth to a local bar were Alec picks out a subject.
“What’s your story?” Alec asks John as soon as we order drinks. And so John tells his story. He’s a builder, off early for the day from a job. He has a cabin he’s building in the north woods and someday he plans to retire there. “I want to get up there and replant a lot of the trees,” he says.
“That’s a real good story,” says Soth. “Can I tell you my story? I’m a photographer…I’m drawn to dreamer types–people who dream big. Something told me you were a dreamer.”
Soth asks if he can take John’s picture. Finding out John lives nearby, he further asks: “Can we go to your house?…I’ll buy you another one of these.”
The complete article can be found here.