"Most science-fiction novels could be easily be turned into fantasy by changing starships back into ocean-going vessels. Frank Herbert’s Dune would fit right with the best medieval romances, if planets became continents and the spice became a source of magical power instead of a drug necessary for space navigation. There is nothing new under the sun or beyond it, either.

The novelty and freshness you’ll bring to the field won’t come from the new ideas you think up. Truly new ideas are rare, and usually turn out to be variations on old themes anyway. No, your freshness will come from the way you think, from the person you are; it will inevitably show up in your writing, provided you don’t mask it with heavy-handed formulas and cliches.”

Orson Scott Card in How to Write Science Fiction and Fantasy