Incorrect grammar, spelling, and punctuation show you don’t care enough to learn the mechanics of writing. Working with you in the future will be a continual clean-up process, and editors want mss as clean as possible to reduce cost of copy editing.
9. Poor pacing
The book should rise through a series of plateaus of action or intrigue followed by breathers. A breather happens when the protagonist is not in danger or actively solving the case. Breathers become shorter and shorter as the plot shifts into high gear. The interval between breathers gets longer as the book goes on, so that by the last 50 pages or so, there aren’t any.
8. Telling, not showing
Many new writers take the shortcut of explaining a situation or backstory directly to the reader, spoon-feeding character development and plot events. Instead, show the action as it happens, letting the characters participate first hand in real time. A detective visiting a crime scene can be told to the reader in a few hundred words, but if it was shown to the reader in several thousand words, the reader could enter the scene and experience it with all senses on high alert.
7. Ending not satisfying
Readers look to mysteries for the kind of justice that sometimes eludes them in the real world. Wrap up all subplots before the resolution of the main plot, so that there is nothing to distract the reader in that last dash to the ending. If you use a wrap-up or epilogue at the ending, don’t drag it out too long. If you're using a twist ending, make sure it's plausible given the rest of the buildup in your book.
6. Violating MOM
Means, Opportunity, and Motive form the basis of a crime puzzle for the reader. Make sure all your suspects satisfy MOM to some degree, so they can seem plausible to the reader. Your killer has to have MOM pegged, something the protagonist will uncover gradually.
5. Location is overused and/or uninteresting
Some locations (such as California, Florida, and Texas) are well-represented in the mystery market already. Editors are looking for new, highly original slants on old locations, or fresh locations that have some intrinsic appeal. Location should have a strong effect on the characters, the crime, and how the crime is solved. Let the setting become a character in your book. If your book is set in Chicago but it could just as easily have been San Diego, then your setting is far too generic.
4. Clues/solution of whodunit too obvious, or conversely, indecipherable
Play fair. At the end of the book, the reader should be able to backtrack and rediscover the clues laid out. Determine all the major clues needed to solve the crime, then go back and sprinkle them into your book out of logical order and concealed, using misdirection and false clues to keep the reader guessing. But make sure that all the clues are there that the reader needs to solve the puzzle.
3. No “hook” at the beginning of the book
The first 500 words of your book are golden. That is the amount a browser might read in a bookstore, pulling the book off the shelf and examining it. In those brief words, you have to anchor the reader in a character, a situation, and a location. Don’t rely on overused beginnings such as the dream, describing the weather, or having the character wake up and go through routine morning activities in detail.
2. Dialogue stilted
Bad dialogue is a constant irritant. Read your dialogue aloud – better yet, have a group of friends read it while you listen. If your characters are saying things that would never come out of a real human’s mouth, you’ve got work to do. On the other hand, dialogue is usually not a word-for-word representation of the way real people talk. It is condensed, more like the way we wish we could have said the things we did.
1. Voice not engaging
Voice is a combination of your protagonist’s personality and your own writing style. Style consists of your word choice, sentence structure and length, tone (humorous, dark, etc.), paragraph length, chapter structure, pacing, and point of view. Editors are looking for a “fresh voice," meaning something that is not a rehashing of other authors’ work, something with genuine sizzle and a new way of looking at the human condition. But not so fresh that readers won't be able to understand it or settle into it comfortably.