You sign up. They send you several daily digest emails of stories for which media people need interviewees. It could be a pet-insurance newsletter, InfoWorld magazine, CBS’s morning news show, Marie Claire magazine, or some dude’s blog. They might want to talk to people who have helped their arthritis through diet, or have a funny zoo experience, or have experience with cloud computing.
As an author, the best-case scenario is that I can help someone with an article or show that is directly related to my book. The worst-case scenario is that my zoo story is credited to “a reader.” Between those two ends of the spectrum is the chance that I’ll be credited as “Esri Allbritten, author of the upcoming mystery, Chihuahua of the Baskervilles,” and that it’ll happen in a forum that reaches bajillions of potential readers.
I also pass leads to friends and family, ’cause this both endears you to people and reminds them that you exist. Make sure your email signature line is in good shape.