How to Write a Successful Prequel
By GerithorDunedain

We've all been watching a movie or reading a book before, and sooner or later we all wondered the same thing: What happened before this? What happened before that caused your favorite character to become the way they are now? Or even more importantly, what was going on in the world before?

Sometimes, there is no answer to these questions. That's where you decide to come in! Many characters simply don't have a backstory, and, being the curious people we are, we want to know every little detail. In many cases, you can make these details up yourself! Forge your own story for them, and decide how they get put on the path of whatever adventure they sprang from. Or alternatively, go back even further than that! Write the story of their parents, or some character that was a big influence on their life. Those side characters have lives too, you know! They're not just sitting there waiting for the main character to come along (in most cases anyway). The following steps will help you plan out and write a prequel worthy of cinema (Or just a really kickbutt book)!

Step 1: Choose your own adventure!

Nobody wants to read a repeat of the original story. Come up with your own! There are several key parts to this that are a unique part of setting up prequels. Really put some thought into these, because they will determine whether your story fits in with the original work or is just a poorly written plot bunny.

A. There's a time for everything

The time in which you place your story is probably the most important element to consider. Make sure that the time you choose makes sense, and doesn't conflict with any other information that's already out there (or canon as most people say). For example, if Aragorn is supposed to be off fighting orcs, you shouldn't have him falling in love with your random elf OC(who most likely has a completely unpronounceable name) on the other side of the world.

B. Location, location, location

On the note of the being on the other side of the world, just don't. Most characters tend to operate in a very specific part of whatever world you're writing in. In the Aragorn example, a prequel Aragorn would be in western Middle Earth somewhere, not on Mount Doom in Mordor. In another example, a character that tends to be a homebody from the U.S. shouldn't be part of an exchange program in England just because. If you're going to have them be somewhere unusual, you better have a good explanation for it.
If you're writing about a character on an important quest or a character who likes to wander, you have much more creative freedom. Exploring new parts of the universe you're writing in can be quite fun, and very engaging for your readers. However, a good rule is to at least start your story somewhere familiar, so readers feel like they're still in the same world.
Writing your entire story in a familiar location has its merits, but writers have to be careful not to use this as a crutch. While it tends to give readers a stronger connection between your work and the original story, it can also be boring and feel too much like the original story. The best option is to mix a little bit of new in with the old and familiar.

C. My, how you've grown!

One of the biggest problems writers seem to have when they write prequels is character development. Although everyone likes the guy/gal at the end of their arc, or after they've learned their big lesson, you can't use that in your prequel. They haven't learned it yet. My favorite example is Thor from the Marvel Cinematic Universe. In the original Thor movie, he starts out as kind of an arrogant tool. By the end, he has learned humility and respect. That was his character arc. Arrogant Thor is humiliated and learns to respect others through his humiliation. But if you have humble, respectful Thor in your prequel story, it entirely defeats the purpose of him learning that lesson in the movie. Don't be the person who robs the original story of its potency.

Step 2: The Baby's Guide to Not Plagiarizing for Babies

This is probably an obvious statement, but don't plagiarize.
I can hear you all groaning, but let me explain. It's surprisingly easy to do this in a prequel. You have a completely fleshed out story that you're basically adding to. All too often, the prequel turns into a copy of the original story. There's several reasons for this, but you have to be very careful that it doesn't happen.
"But random author dude," you gasp. "Where can I learn this skill?"
Not from a Jedi.
But seriously, it's pretty easy to avoid if you're looking out for it. The main reason this happens is because authors rely on the original content too much. By original content, I mean the characters, locations, and plotlines of the original work.

Say you're writing about young Luke Skywalker. Due to his uneventful childhood years, I wouldn't recommend doing that at all. But let's just say you really want to do it anyway. You decide that, hey, every protagonist needs an enemy right? So you add a dark, mysterious Sith. But why would young Luke have enemies? Because they have kidnapped his lady love! But young Luke is so weak and fragile, there's no possible way he could save her alone! Insert older mentor figure, and some side characters (one of them would almost definitely be for comic relief, because who doesn't like funny side characters?). So Luke and Co. go forth and save the lady! But Darth Stereotype will have none of that. In the rescue attempt, one of the side characters dies! Mentor guy already taught Luke the lessons he needed, so we can just kill him off, right...?
Wait... This all sounds startlingly familiar! *cough* A New Hope *cough* (All of you who haven't seen Star Wars are probably really confused right now, and I'm sorry).
That's because you basically just rewrote A New Hope and slapped a new (probably worse) skin on it.
Don't do that.

Step 3: Research, research, research!

Imagine you've already written a successful book. No, that's not good enough. I mean actually imagine it (or not if you already have, in which case I offer my condolences for having to read this article). Now imagine you're scrolling through Wattpad, when oh joy! You discover fanfiction based on your work.
"I shall read this!" You exclaim to yourself excitedly while drinking the world's most expensive coffee from your gold-engraved mug. You click on the story, your heart soaring with excitement that someone loved your story enough to base one of their own off of yours.
*fast forward an hour*
You are a sad, blubbering puddle in the corner. "Whyyy??" You scream to the heavens, trying to shake the jarring mental images from your mind. "What have they done to my beautiful world?? Why was [insert character's name here] so creepy?? Why were there mermaids?? I expressly stated that there were no mermaids in [insert impossibly spelled name of a country in your world]!!!"

Naturally, you'd be unhappy if anything like this happened. To make sure that you aren't the perpetrator of such an affront, make sure to do some research. Delve into the world, learn about it. Try to imagine that it's your own creation, and that you wouldn't want to ruin it for anything. A few hours of research can make the difference between a fleshed-out, epic story and a sad mess like Twilight (Sorry Twilight fans!).

Step 4: Why is Katniss a Black Belt??

Once you've done your research, you can begin to apply it to your story. You begin to write your first few scenes. [Insert character name] is a high schooler. She's on the chess team and spends most of her time reading (and writing) bad Supernatural fanfics. She's walking through the hallway when BOOM! The high school bully shows up with all of his friends. Suddenly, she's high-kicking and karate-chopping them all across the school!
Wait what?
No.

Nobody is going to believe your story when your characters are completely unbelievable. And with prequels, this is even more important. The characters you're working with already have interests and goals. And if they couldn't [insert particular activity] in the original book, nobody's going to believe that they can do it in your prequel. This stands true for personality traits too. If the character is a brooding, serious individual in the original work, don't have them making bad puns every five seconds.
This may seem like a little thing, but it's really important. Write the characters in a way that's true to the original work.

Step 5: "And Frodo threw all seven dwarven rings into the fire..."

Your characters are going to have to face something at some point in the story. Whether that's the main antagonist or an important decision, it's necessary for your story to remain interesting. However, don't try to outdo the original story. If the main character's biggest struggle is facing a bully in the original work, don't have him killing a dragon in your prequel (I have no idea what story this would happen in, but I needed an example and that's what I came up with). If you're writing an original character or a side character from the original work, don't have their big act outshine the main character's.
This can be ignored if you're focusing on a canon event that was mentioned or referred to in the original work. Like in the Lord of the Rings, the appendices mention that a hero killed a massive dragon called Ancalagon the Black in the past. He was a lot bigger and meaner than Smaug from the Hobbit. If someone chose to write a story centered on that, it would make sense.

Step 6: Have fun!

All of these suggestions are just that: suggestions. If you just want to have fun, all of these can be disregarded. These are just tips for writing a good, fleshed-out prequel that would fit right alongside the original work. If that's your goal, I wish you all the best of luck, and if you need any help feel free to contact me!