In books, we often trust the narrator of the story and accept the secrets they reveal. But not all narrators are trustworthy. Have you ever considered using an unreliable narrator to spin lies for the readers of your books?
Liar, Liar, Pants on Fire
Some narrators are unreliable. It's a rarely-used but quite effective literary technique. When it's done well, it will lead to a shocking twist ending that takes readers by surprise. One of the best examples of this technique is The Murder of Roger Ackroyd, by Agatha Christie.