Readers' advisory - helping a person find books to read - is pretty much the best. It's a fun challenge to find out what books a person will enjoy, and it feels like a big win to find someone the perfect book.
When librarians do readers' advisory, we tend to be thinking about what we call "appeal factors." These are the different reasons why a person could like a book. For example, Alex might like Rick Riordan's Percy Jackson books because of the mythology, while Beth might like them because they're funny. If I can find that out, then I'll recommend different books to those two patrons.
Finding out can require some sneakiness, though. "Why did you like that book?" can be a tough and confusing question to answer, and can make people freeze up. If, on the other hand, you encourage a reader to talk about some books she liked, you'll often hear, "It was so exciting, I read it really fast!" or "It was hilarious" or "It has all these creepy monsters that are really cool."
At our readers' advisory training, we talked mostly about four types of appeal factors:
- Characterization (includes character development, size of the cast, point of view, whether characters are likeable, and whether the same characters can be followed through a series)
- Story (incorporating genre)
- Frame (includes setting and tone)
Just today, someone told me that she usually loves thrillers, but couldn't finish Gone Girl because the pace was too slow for her. A different person told me that she couldn't stand that same book because she didn't find any of the characters likable. Different people care about different appeal factors. And, of course, what they want can vary with their mood.
Unsponsored plug: If you have access to NoveList (your public library might!), then you can search books by appeal factor. That might be something like "nostalgic and bittersweet" (falls under Frame), "leisurely paced," "large cast of characters," or "intricately plotted." It's a pretty fun tool to play around with.
Thinking about appeal factors for your own stories can help you come up with good comparison titles if, say, you're querying agents or publishers. It can also give you useful ways to describe your stories in general. Plus, it might help you find your next book-soulmate!