I try to weave a secret into each plot. It's the thread that holds the rest of the story fabric together. In fact, it's the reason for the story. I hint at the secret early on. Immediately I want the reader to get the feeling that something here isn't quite right. It helps maintain the suspense if a puzzling element is introduced in the first few pages of the book, but the answer isn't revealed until the final ones. Hopefully, readers want to know what the heck is really going on, and it's the desire to find out that keeps them turning pages.