The engaging powers of writing

Samuel Johnson said, "The two most engaging powers of an author are to make new things familiar and familiar things new."
Let's look at that sentence for a moment. Johnson uses the word "engaging" - getting the reader connected or tuned in, and he refers to "powers of an author" for, indeed, a few well chosen words have the power to change the world.
"Making new things familar" means to allow the reader to understand what you're writing about. When you are reading something, the content should not remind you of your first day in algebra class. It has to be simpler than that.
"Making familiar things new" means to shed new light on old subjects or write with such a fresh approach that the old seems new.