Photo by Walt Stoneburner
1. The book is by an already established author who can get away with more.
2. The author is dead.
3. The agent picked up the author over ten years ago or the book was published over ten years ago.
4. The book was first published outside the U.S. (Brits are apparently more patient with pacing).
5. The book is non-fiction.
1. You revealed too much in the first part of the book, whether that be about your characters or the plot
2. Secondary or subplots have knocked you off course or run away with the story
3. The conflict (internal/external/sexual) is nonexistent or weak or there is no real action
4. You don't know what comes next so you're meandering around aimlessly
5. The story is boring you or you realize you have major plot problems that are making the story illogical or unrealistic
1. Strive for constant change with increasing tension/difficulty--Picture your character driving down a race track, it can't be a smooth, straight road ahead. Throw a speed bump in her way, then when she deals with that, put something in front of her that is even more difficult to manage (a herd of cows perhaps), and just when she's maneuvered around the bovine, have the wheels fall off the car.
2. Give the character new information in small pieces--a hint there, a clue here, a fleeting expression across her friend's face that makes the MC wonder if the friend's being honest, etc. And make getting those clues hard fought. Don't just have the clues fall in their lap, make them work for it. Give your reader just enough to want more, but also let them feel like he/she is closer to figuring out what's going to happen.
3. Keep your character's eyes on the prize--You cannot lose sight of your characters' goals. Every scene they enter needs to be striving toward whatever goal they are seeking. Your characters should enter each scene with a purpose--what are they trying to accomplish in this particular scene?
4. Don't be repetitive--Do not have scenes rehash old information. Each scene needs to add something new. And this also goes for having scenes that "feel" too similar in setting, content, tone, etc. If your hero and heroine are always having "let's figure out this mystery" conversations over a meal, your reader is going to get bored. Change it up.