by Jill Williamson
When I wrote my mystery vs. suspense post on Tuesday, I tried to link to this post. Then I discovered that I never posted this post on Go Teen Writes. This was one of my last posts on my old Teenage Authors blog. So I decided to post it here for those of you who’ve never seen it. I think it’s helpful when writing a mystery.
The strength of a plot depends on how the writer reveals information to the reader. If you have nothing going on in the middle of your book, try some of these mystery tips to see if you can add some intrigue. And if you don’t have enough characters for intrigue, maybe you need to add some minor characters.
1. Know the ending
When writing a strong plot, it’s important to have some idea of how you want the story to end. This usually results in your main character achieving his goal. In a mystery novel, that means figuring out who done it. If your mystery is a subplot, you still need to reveal the answer to that mystery. Once you know your ending, it will be easier for you to plant clues and red herrings for the reader along the way.
2. Avoid luck
Nothing is more frustrating to a reader than a story in which the main character succeeds by a string of good luck. Do not allow luck or other heroic characters to sweep in and steal the spotlight from your main character. Your hero needs to solve the mystery!
3. Backstory
Know the backstory of all your main and minor characters. Do not put all that you know into the book! You need to know it to understand each character’s motivation for doing what they do in the story. Murder requires motive. So does every other action. Once you know each character well, it will be easier to plant clues and red herrings for the reader.
4. Introduce the culprit early on
Make sure the reader gets to see that bad guy/traitor/guilty party early on in the book. It’s frustrating to be reading a story and think you know who may have done it only to discover it was a character who just entered the story in chapter 28! Give the reader a glimpse early on. JK Rowling does a great job with this. If you’ve read or seen the first Harry Potter, remember that we first saw Professor Quirrell at the Leaky Cauldron when Harry was first headed to school.
Keep in mind, the culprit shouldn’t always be the least likely person. Mix it up. Keep your reader guessing.
5. Clues
A clue is: anything that serves to guide or direct in the solution of a problem or mystery.
Plant clues as the story moves along. Things that may seem significant or completely ordinary. Harry Potter’s meeting a new teacher seemed like no big deal at the time.
Clues can be observations. Perhaps your character notices a tattoo on a friend. He doesn’t think much of it until later in the book when he sees a villain with the same tattoo. Then there is a connection that raises suspicion of the friend.
Clues can be relationships: relatives who hate each other, a boyfriends who was cheated on, a couple in love, a mentor…
Clues can be evidence like fingerprints, hair color, footprints, license plate numbers, etc.
Clues can be dialogue. Keri told me she loved snowboarding. Then why did she tell me she hated it?
Depending on the type of writer you are, you might plan these clues before you write the book or write the whole book then go back in and plant clues. Both ways work.
Use clues sparingly. You don’t need them for every character in every scene. You just need a few here and there.
6. Red herrings
A red herring is something intended to divert attention from the real problem or matter at hand; a misleading clue.
Plant red herrings as the story moves along. Things that may seem significant or completely ordinary. Professor Snape’s apparent hatred of Harry seemed like a very big motive for villainy, even though it wasn’t.
Red herrings can be observations, relationships, evidence, and dialogue too. Reveal them in the same manner as you do clues. You goal is to throw your reader off track.
Depending on the type of writer you are, you might plan out these red herrings before you write the book or write the whole book then go back in and plant red herrings. Both ways work. 
Use red herrings sparingly too.
7. Wait as long as possible for the big reveal
If the mystery subplot is integral to the overall plot of your story, don’t reveal your culprit in the middle of the book. Wait until the last possible moment for your main character to figure it all out.
The idea is to create a trail of puzzle pieces for your character to find and put together until it’s time to be revealed. So if your story is stuck, I suggest you plant some more puzzle pieces. Any questions?