Here’s a handy tip from journalism professor Dewitt Reddick. When you want to define some new thing, connect it to three bits of other knowledge for the the reader: the superordinate category of which the new thing is a member; a sister thing in the same superordinate category that is sufficiently different; and an example (the more concrete, the better).
Here’s a picture:
Suppose someone doesn’t know what a cat is. A Cat is a kind of animal; a sister thing is a dog, which is also an animal, but it goes “Woof!” and licks itself at odd moments; and an example of a cat is a domestic shorthair.
The semantic relations between these concepts are: “is a member of,” “has sister,” and “exemplified by.”
This tip is recounted in Jack Hart’s book, A Writer’s Coach, which is good but not great, in my view.