I heard someone talk about this a while back and I 100% agree with the thought process here. When you begin writing, the first step in creating the world that you’re setting your characters down in is to determine what can happen and what can not happen.

Remember the basics; Who, what, where, when, why, and how?

Let’s take me for example. I write historical fantasies. One of my major vices is people who get historical details wrong, or try to place their story in a time that actually happened, alter a lot of history, but expect everything that happened in history to still flow normally.

“It’s said that if you bend but one blade of grass, you run the risk of altering history.”

You’re not going to tell me that certain things just… happened, changed history from how we know it, but everything proceeded normally. Sorry, that’s too much to buy for me. Now if your goal was to create an alternate future where some things are the same, but there are small differences between our world and the one you’ve created, great! That’s something I would love to read about.

So when I write my historical stories, one rule that I absolutely must follow at all times;

Nothing can happen in your story that would change History. Your story can influence historical events, but only so much in that they influence events to happen AS THEY ACTUALLY HAPPENED! Otherwise, you’re going into a type of story that, in my opinion, falls outside the realm of historical fantasy/fiction.

So back to basics:

Who? This applies to both Historical and Fictional Characters.
What? Historical Events.
Where? A place of historical importance.
When? A time period of historical significance.
How? … well for me, I make sure that my story influences events so that they happen as they should.
Example: One character in one of my stories is moved by the events in the story that he lays down his sword and refuses to take up arms again. This actually happens in this character’s history and results in a major historical event.
The other option I use is to essentially keep the story out of History’s way. Essentially this means that the story happens in a setting that really never made it into the history books or was simply never chronicled.

All of this is just one example of rules that can/should be used when creating a story. I’m not saying that there is a specific set of rules that need to be followed. You create the rules and you stick to them. It not only helps continuity, but it keeps the readers understanding of what’s going on intact.

Another good example is Magnifica. If/when a character dies, why can’t the enchanter just snap his fingers and bring said person back to life?
Well because that falls outside of the enchanter’s rules.
Enchanters can’t interfere with the nature of the Universe. An enchanter tainted by darkness cannot effectively use healing powers. The use of dark enchantments corrodes the soul and will result in the enchanter’s eventual death. In 2013, there are no enchanters to learn from, so anyone who discovers that they have powers are limited to what information they can find on how to enchant… and there isn’t much information left.

Rules are a useful tool to staying on course and explaining why a story involving super natural elements can’t be solved with the flick of the wrist.

What happens when rules are overlooked? Well… as much as I lament using this as an example…

Perhaps the biggest plot hole in one of my favorite movies that was never explained. Why couldn’t they just ride the Eagles to Mordor?
Unfortunately it’s the one that fan boys like to pick at, but it could have been resolved if a rule was put into place to explain it:
The Eagles feared Mordor for some reason.
Sauron had some kind of force-field in place to prevent them from getting there and it would only collapse once he was dead.
The orcs had large ballistas that could be used to shoot down the Eagles so it wasn’t worth the risk.

Any one of those would have been fine, but instead it was never addressed.

So yeah, rules in a story that the characters must follow are very important and it’s a good idea to have them spelled out early on so that there isn’t confusion and it doesn’t look like your just making things up as you go later on. Good foreshadowing also helps with creating rules.

So that’s my 2 cents. Hope it helped!

See you on the flipside!
-Jim