A couple things I do are more tone related than rules related.
No magic shops: Magic is rare and valuable, no one sells it. If someone were interested in setting up a shop, the persons wealthy enough to purchase magic would be too rare to make it a viable business. To balance this out, a local alchemist or apothecary can sell healing droughts, as this is more subtle magic.
Obvious Magic is Scary: Normal people run away when someone can shoot flames from their hands, or transform into a bird. Some people might even form a posse complete with pitch forks and torches.