There comes a point in creating a magic system you have to decide: What is magical and what is mundane?
When I say magical there I mean the sort of magic that is hidden and reverent. The sort of magic that is spoken about in whispers and veneration. This is the magic kept secret and passed down and down and down until it is as much myth as magic. The magic that, despite being as real as anything else, has passed into legend.
Then there is the other sort of magic, the sort of magic imbued in everything a character does. It is in the sweep of a hand and a muttered word to light a fire. It is in the quick stitches to fix a pair of socks. It is in the glimmering songs sung to a child. The second nature magic. The everyday magic. This isn’t the magic beholden to a wizard in a secluded tower.
This is not to say that the two are mutually exclusive– far from it. Instead, when creating a magic system for your world you need to find the line. Is your world the sort of place where you can hop down to the general store for a magically-imbued potion, or is it the sort of place where magicked healing is myth, a legend, something for your protagonist to search for? Or can they go to the general store so some ailments, but others are far outside the reach of a local hedge witch’s power? It’s the middle ground– the magical mundane if you will.
My personal tastes run as magical as mundane. I love it when magic is within everyone’s grasp, not something confined to ivory towers, or blood, or some fated destiny. I’d much rather a story where magic runs through the world as immutable as life and death. Magic is not confined to that destined party of three who will save the world, it is with everyone, a force for all rather than a few. However, that’s just me.
To give yourself a grasp on where your line between the magical and the mundane is try a day long writing activity. Here is what you are going to do. For one day write down absolutely everything you do. Write down the minutia of your day. Seriously, if someone else was to read this account of your day, I would want them to think the phrase horrifying detail, then back away slowly.
At the end of your day, sit down with your list of activities and consider one of your WIP’s magic systems, then write down how a character would go about that in your world, what level of magic or mundane would they use for it.
For a quick example, let’s go with what is probably the first thing on people’s lists: waking up. My guess is you do this by an alarm clock or a phone or a combination of both. How do people in your work in progress wake up? Is it through mundane means, magical means, or magically mundane means? I’ll use an example from one of my WIPs. Pulling from the victorian tradition of knocker-ups and combining it with some magic I’ve got some magically mundane ways of waking up. Rather than having people use sticks or batons to use slam onto doors to wake people up, used the fact that fire magic is prevalent in the area. The magicked up knocker-ups use itty bitty fireworks at windows to wake people up. Not the greatest job in the world, but not bad for a young mage in training.
You might be surprised at the solutions you come up with for everyday problems. How does your world deal with public transportation? Who makes bread? How is grain ground? What is your world’s sewage system? Is there a way to recycle? Where do clothes come from? Who mends them? Constantly ask yourself, could a character do this with magic? Then ask yourselves would a character do this with magic? Are there systems in place for that? Is magic or mundane the answer?
I’m not saying that you need to include every single one of these in a story, unless you want to create a 10,000 page monstrosity of worldbuilding. However! Worldbuilding is in the details as much as it is in your hand drawn maps and your nation’s power structures. Worldbuilding is in the everyday. So if you want to show how magic permeates every aspect of life, than give us some examples. Show us the background of a rich, fully thought out world.