Writing convincing fantasy fiction is harder than it looks, argued J.R.R. Tolkien in an essay in 1947. Any old writer, he said, could describe a “green sun”. Many of them could even imagine it. But building a fantasy world “inside which the green sun will be credible…will certainly demand a special skill, a kind of elvish craft.” Tolkien himself was undoubtedly born with that “elvish craft”.
To help him create a believable “Middle-earth”, the setting for “The Lord of the Rings” and “The Hobbit”, Tolkien produced hundreds of drawings and maps. They grounded his stories and helped him to keep track of thousands of years of history, sprawling geographies and complex languages.
Tolkien got so popular that people always think the rest of fantasy is cliche or done before. He popularized old european folk tales that were reframed in his own epos so good, everything else seems like a rip off or to much the same.