I think that if you want to go that method, you should really lay the flattery on thick. Make sure they know you really enjoyed their story they’re a great writer, and hey would they mind checking out your story? Make it seem casual, I think this’ll help with the people who hate that approach because a lot of people do. Also, if they have a sci-fi book or whatever, and you have a PJO book or whatever, they are not the person to send that message to. I really hope your book gets more reads!