Creating a fictional world has a lot of challenges. You’re crafting a tiny world to sit in the palm of your hands. To be believable, it must contain the details that breathe life into the dollhouse. When you’re writing fantasy (not in all fantasy, but in most), magic is a key driving force within your plot and your setting.
Magic is incredible. It opens doors otherwise unavailable, capturing your reader’s imagination in a huge way. But it’s tricky to get just right.
I’ve already talked about some of the aspects that build a solid magic system. So let’s get into the details.
What is the source of your magic?
This can take so many different forms. It can be anything from God’s divine blessings, to ye olde element wielding mage, to quiet psychic dominance from within. Whatever you decide to use, it will shape your magic in every way, standing as the backbone of the process you create. Not only does it serve a function in your story, but it can help drive and mirror the themes you’re presenting, adding that much more punch to the whole package.
Let your creativity run wild. But remember some themes it will impact as you go, intentional or not. It can be easy to accidentally weaken your own message with an opposing type of magic.
Don’t get me wrong, clashing ideas can be powerful. If used intentionally, juxtaposing two themes can make each other stronger. But that tactic needs a little planning and an awareness of what you’re writing in the first place: It’s totally possible to write about a chosen one choosing choice over fate, and it can be a great—and often surprising—story.
Keeping these themes in mind will make your work stronger and more seamless, adding more punch and depth to your message and making it an overall more memorable read.

External vs Internal
This is the difference between harnessing forces in play around you—anything from Gods to entities to natural elements—vs creating your power from within. When simplified to this level, you can see just how much impact this decision has.
It’s the difference between control and creation, which, as a theme, can leak into every other aspect of your message. So give it some thought and look at your story before you decide which direction you want to go. Then you can use it to its full potential.
Fate vs Choice
Part of deciding your source is deciding how your casters reach that source, at the most basic level. (Not so much the mechanics of DOING it. That comes a little later.)
Here is where you end up with a chosen one given Zeus’ blessing, or a cabal of mages spending their lives in study. Both are vastly different stories, with different messages and different themes. With some creative thought, you can blend them together as well–A chosen one fights a cabal of studied mages who stole God’s ashes for power? Why not? Either way, it affects your theme.
Another thing to consider is accessibility. Does anyone have the capacity to learn, or only those born with a special birthmark connecting them to the moon? This decision can impact not only your story, but how your reader relates to it.
On one hand, if you opt for the idea of innate, born abilities, or the ‘chosen one’ concept, it can give your reader a sense of wonder, letting them touch the idea of being special or different. It puts them in the shoes of the chosen, albeit in a less personal way.
But then, if you go the other route, where anyone can learn with the right teaching, your reader might feel a little more drawn in, rather than just bearing witness to something spectacular. It lets their imagination run with the idea that they too could learn, in the right world, in the right time.

Until your power source is well in hand, it can be hard to move to the later stages with clarity. You might find stumbling blocks you hadn’t considered or plot holes you have trouble filling. Building a system of magic is like building anything else—you need to do it from the ground up.
Magic is tricky enough to incorporate as it is. It can cause a huge dramatic headache if you make it too powerful or it can become super confusing or contrived and silly. Ultimately, you want to establish a strong system of magic that supports your work and adds to it, rather than just existing around it. You need to incorporate it into every other part of your work or it can feel tacked on. Having a clear understanding of your power source lets you do that.
As fantasy readers, we love our magic. It captures our imagination like nothing else. Give it the foundation it deserves. No one likes a flooded basement.