Let's talk magic. If you're dealing with fantasy, whether it be High Fantasy like Tolkien or Urban Fantasy like Supernatural, magic is going to make its way in. It's inevitable. Even within my own novel, The Paladin, magic isn't a main focus but still has its moments. So, because I know it'll come up at least in some small way and probably much more in later additions to the universe, I've had to work with my own magic system. And let me tell you... it gets complicated quickly.
In fiction we tend to classify magic in two groups: hard magic and soft magic. There are other names but the basic concepts are pretty simple. In hard magic, there are rules. You have to have this or say that in order to make a spell work. The spell has hard and fast limits. It is well-defined and follows a strict code. Now, you can make that code or rule set as complicated or simple as you wish, but for hard magic there has to be limits and rules. Think something like Harry Potter. You need a wand. You have to say the spell. If you don't know the spell, you can't just make stuff happen. Every spell has its use and that's all its good for. That's hard magic.
Now soft magic, as you might've guessed, is the opposite. It's amorphous. Opaque. You know that magic is happening, but how it works is beyond the reader's comprehension. Likely, it's not even important. Let's look at Lord of the Rings. What are Gandalf's powers? I mean, we know he's super powerful, but what can he do? Well... he can make his staff explode when he slams it down? Um... blow intricate smoke rings? Oh! He can turns waves of water into rushing horses! You see, we don't really get a laundry list of Gandalf's abilities. Frankly, he isn't super important to the plot. He shows up when needed and his abilities move the plot forward, but whatever rules for his, if there any, are never established. He can just kinda... do what he needs to.
Hard magic tends to be something that you can put into a protagonist's tool kit, something for them to draw from. It requires attention to detail and consistent continuity. Soft magic is more of a plot device, though. Whatever you need to move your story forward, that's what it does. You rarely see a main character with soft magic because, well, that's boring. Soft magic solves everything without any real limits. But when your protagonist uses hard magic, well, now you can make predictions. Hmm... he's trapped in a cave, well, I know he can summon fire to light his way. Oh! And for a least a few minutes a day he can contact someone telepathically! Maybe he'll try to get help. But you never know what's going to happen next with soft magic. Same situation, maybe they channel a portal or force the cave walls to open up to the surface. And since it's soft magic, we don't need to have known that was possible before.
I'm not saying one is better than the other, though I will say as a writer, hard magic is more fun to write. You're building something with it. You're setting rules and creating something concrete. In fact, in the writer forums I frequent, I don't think I can go a week without someone posting to ask for people to look over their magic system. If you have a system, if you need people to check for logic, you know right away it's a hard magic system.
Be Excellent to Each Other
Keep your eyes open for my debut novel, The Paladin.