Reading widely not only broadens your vocabulary, it also expands your mind and exposes you to new concepts and ideas you would never have dreamed of.
You learn different writers’ expressive styles and, in the process, develop yours.
It’s the little details that make your book come alive, the little semblances of truth within the fiction that allows readers to lock in and relate to your writing.
Make time to read everyday. Go out of your way to find and read something you normally wouldn’t be interested in reading, something that has nothing to do with your concept or the story you’re writing.
Pick a topic like geology, history or philosophy; anything you wouldn’t normally read.
Read up about it on the internet, or find a book about it in your local library (or online) and read up on it.