The most important rule that I made for myself was to never use the word 'magic.' Even more importantly, there would be no universal word to replace magic because magic represents too many things, so even if the term did exist, no one would bother using it. Instead. magic is represented in more prosaic terms such as secret, skill, technique, or knowledge. The immediate benefit of using these words is to put the reader in doubt about what is magic and what isn't magic, making this whole idea of magic far more unclear.
For example, the Ironmongers know the secret of mass producing iron into steel by using a blast furnace. Now, is this really magic or is it technology? The answer is that it doesn't matter. This technique is making them a fortune and they kill to keep this a secret.
Behind all these terms comes the idea of limitation. When people hear magic, they think of limiteless possiblities. Anything can happen with magic and often does. Magic is wonderful and mystical and powerful. If a wizard can just as easily change your shape as protect you from fire. It's all magic. It's all equal. On the other hand, secrets are only secrets when kept secret. He he knows a secret has no incentive to devulge it, usually as gaining that secret had a cost. The secret of changing your shape in no way implies the secret of protecting you from fire. Secrets imply limites, and rather difficult limits at that. With secrets, all things may be possible, but few know each answer.
Skills and techniques also work well with limiting magic. A master swordmaker will spend a lifetime perfecting his technique in making a single type of weapon. Part of that is the secrets of steel, but an equal part of that is experience and training. Just reading a book or learning a secret won't give you enough information to produce a sword. The great implication of this is that producing a sword is as much a work of magic, and as equally capable of producing a magic weapon, as a wizard with some book. It pulls magic out of waving hands and chanting words, pulling it into the experiential. Thing which did not seem magic before seem magic now.
The truth is, raw magic blinds us with our preconceptions of men in pointy hats with staves and spells and near super-powers. Only by pulling it off the table to we see that magic can take a myriad of other shapes, working its way down into culture and language in ways that had not been considered recently.
Why do I say recently? Because we know what a society based on magic looks like. The pre-modern world assumed magic. Look at China and Medieval Europe, and you will see societies based on the ideas of magic. All the world was magic to them. Professions, dependent on the goodwill of saints or spirits or minor gods, made sure to keep up their rituals. The state had a magical and divine explanation for why the rulers should rule, and why you should obey their laws. It's all there if you are willing to see it. What makes it magic was not the fact of it being magical but the presumption of the people that it was magical.