Fantasy fiction takes many shapes. But one of the most common themes is magic. Because of this, creating your own fantasy world demands the creation of your own magic system.
Magic can be simple or complex. It can stem from any number of inspirations and can fill any role you can dream for it to take. It can be explosions and fireworks, or it can be quiet psychic dominance. Maybe in your world it’s a utilitarian replacement for mundane tasks. Either way, if you include it, magic is an important aspect of your world.
But, if you are including magic in your project, you’d better understand how it works. Magic can be uniquely challenging to write, as it often has unseen components and multiple working parts, with only a chosen few understanding what makes it tick. Have you ever written a mage duel, trying to keep a snappy pace and clear action flow? Good bloody luck. It demands an elevated level of description, so if you don’t have a crystal clear understanding of how your own magic works, it’s easy to lose the sense of urgency.
Creating a magic system is a massive undertaking, demanding a lot of thought and likely to have its details changed as you work through your first draft. But that shouldn’t scare you away from using it. It’s a powerful dramatic tool at your disposal, if you use it right.
So, what are the components of a unique magic system?
I’ll get into each of these in greater detail in following posts, but for now here are some of the aspects I like to consider when I develop my magic’s shape.

Source
Where is your magic coming from? Inner psychic powers or demonic guides? Do you tap into the natural flow of the great world tree? Maybe the flying spaghetti monster imbues your casters with its blessing. Whichever direction you choose, its important to pick it and be consistent. This is the backbone of your magic, and the better you understand it, the clearer everything else will be.
On another level, here is where you should decide the connection between your magic and its casters. Are you born with the ability to tap into the power, or is it something you learn over a lifetime of study? Can anyone learn it with proper training, or only a select, special few? Give this some thought, as it makes a big impact on the theme of your story. Fate vs choice, to name one example.
Method
Very simply, how do you cast a spell? Here is where you really bring your magic to life, so make it count!
Your method is more than the physical display surrounding your effects. It’s the bridge between the source of your power and the spell itself. Do you move your hands in specific ways to direct the energy? Or maybe you throw a pinch of herbs that have been steeping in moonlight for a full lunar cycle. Either way, your method shapes your magic system into something tangible, giving it the aesthetic it will carry through your story.
Take some time to decide what theme you want your magic to have. Its important. Ecstatic dancing looks much different than chanting in Latin, even if both throw fireballs in the end. Similarly, waving a wand is much more external than brandishing your inner psychic prowess, which again changes your theme in a massive way.
Find the aesthetic that suits your setting and go from there.
Scope
How powerful are your casters? Gandalf, for example, cast a handful of spells in the entirety of Lord of the Rings. He was wise and brilliant and could shape spiffy smoke rings, but he wasn’t throwing the moon at anyone.
If you understand the rules of your magic from the onset, you can incorporate it into your story so much easier. Otherwise, you’ll create huge plot holes that you’ll only catch when it’s so much harder to fix them. (Wait, why would she be stuck in prison anyway when she could just melt the bars? Dammit…)
Another interesting point about scope: When you’re designing your magic, bear in mind that low power often makes for a far more engaging story than high magic. Making things too powerful—unless that power is reflected on both sides of the playing field—robs your story of its teeth.
Make your characters sweat and struggle and wonder how the hell they’re going to survive, rather than handing them the tools to destroy the world. (I think this is also why mentors tend to die in terrible ways. Some clichés exist for a reason.) Epic magic is cool and epic, but limited magic is way more interesting.
Cost
Here is an important one. It’s kind of tied to scope, but I think it’s vital enough to earn its own mention. What is the cost to the caster? There needs to be something, or again, it becomes too easy and sucks the punch from your drama.
On one hand, you could chuck fireballs until you’re blue in the face, skipping to your objective without a moment’s thought. Or, maybe every fireball you throw sucks a year from your life. Well now, that adds a more interesting complication, making it a pretty big decision every time you decide to cast. Is it worth five years of my life to get to the other side of the field? Maybe… but maybe not.
Make the cost of your magic reasonable for what you want to achieve. You don’t want it so steep that no one will use it, but it must be costly enough to give some hesitation. Examine your setting and your themes and decide from there.

Magic, by its nature, usually involves a lot of invisible wheels turning in the background. Not only can that be difficult to express in a concise way, but it can get boring fast if it doesn’t:
1) make enough sense to avoid confusion, and
2) engage the reader’s imagination on a personal level
Firework displays are great, but without the detail behind the fireworks themselves, your reader will be a spectator rather than a participant in your story.
If you’re including magic, in whatever shape you give it, it’s vital that you’ve crafted its rules with the same care you put into your characters, because it has a very real chance of becoming a character in its own right. Treat it with the respect it deserves.