One of the questions was about a novel's structure and its author's decisions about content.
I'm writing a mystery and it has a traditional structure. It begins with a "hook" that gets the reader to decide he likes the idea and wants to read on. Hooks consist of dialogue that makes the reader curious or an event (such as murder) that arouses the reader's interest. I do, however, have a hard time picturing readers as fish.
After the audience is "hooked," the first 25% of the book sets up the characters, setting, some complications, and ends with a major event that sends the main character off into disaster. That event might be a murder or a life-changing experience for the main character. No matter what it is, the major event propels that person down the path of brambles and pitfalls. By now the audience likes the main character (in a traditional mystery) and reads on to see how the author will torture her. The more the main character experiences and overcomes, the more the reader will be cheering her on.
The middle of the book--26% to 74%--extends subplots and adds suspense, hoping to trick the reader with events he didn't expect. (Personally I find this to be the most difficult part to write because I have to maintain suspense.) This is where I start asking "what ifs." In this middle part of the novel, writers try to pull rabbits out of hats. Just when that reader thinks the main character is out in the clear of whatever entanglements she has encountered, the author hits her again with more debris.
Throughout the middle of the novel the author adds subplots and develops them. She hides clues among other innocent items and tries to make them clever enough that the reader won't spot them. She also hides some "red herrings," false clues that seem to be the answer to the riddle--but they aren't. The author may end many of the subplots prior to the climax. This makes for a much cleaner ending.
Toward the end of this middle part, another major event will occur. It could be a murder. Often the very person the reader suspects is the villain ends up getting killed. Then the reader is left scrambling to figure out a new choice for the villain.
To add to all of this plot talk, I should mention that each scene also has a structure of its own. The author wants to end some chapters with "cliffhangers" so readers will want to start a new chapter, thereby keeping them up until 3 a.m. so they will curse the author in the morning and swear they will never read another one of her books. But by now they like the main character so much that they will forget their decision by the time the author writes another book. (Isn't that the way it works?)
The other consideration in plot writing is the idea of fair play. The clues must be there, not just for the sleuth but also for the readers. If the author waits to add the most important clues until the last ten pages of the book, her readers will not be happy. Unhappy readers make for lagging sales. Not a good idea. Give the reader a fair shot to solve the crime along the way.