If you ask people to describe a dragon, they’ll likely have different images in mind. One might think of a hulking beast as large as a castle, with wings like a hurricane and fiery breath that brings death. Another might imagine a guardian spirit with fur as well as scales and more of an affinity for water than fire. And yet another might envision the cute and cuddly Toothless from How to Train Your Dragon.
Similarly, dragons can take many forms, from the stomping, fire-breathing monsters of English mythology to the ethereal creatures of Chinese folklore. Even within a single culture, dragonkind may be broken down into several species (drakes or wyverns), and the details of those animals will differ from account to account. For example, not all dragons are huge, and some of them don’t fly at all.
Most draconic creatures, of course, have scales. But you can go further and give them other features that make them unique to your world, such as barbed tails or feathers, the ability to shape-shift in size or form, or the power to levitate objects with their minds. Dragons also often have associations with specific elements, such as fire or air, and some have the power to change those elements.
In terms of personalities, it goes without saying that your dragons should have distinct ones—just as all sentient creatures do. They might roar, grumble, or growl, but perhaps they also sing, click their tongues, or use movement to communicate, such as the elegant mating dances of Anne McCaffrey’s Pern dragons.