Dear Barbara,
Are you a plotter or a pantser? Do you outline before you sit down to write your novel, or do you sit down at the computer each day, waiting to be surprised, writing your book literally by the seat of your pants? Or are you a combination of the two?
Before you start writing your novel, it is my firm opinion that you need to have at least a general idea of what the story is (plot), who’s in it (characters), and the world in which it takes place (world-building).
It's critical to understand these elements and how they are related.
Plot, Style, Character Development, and Length are always related. Any good novel has exactly the right balance of each, one that is appropriate to the genre and story.
My 12 year old son introduced me to a hilarious series of cartoons on YouTube. It's all about providing alternative endings to popular films. (If you search 'how it should have ended' on YouTube, they'll come up.) Some of them, such as the proposed alternative ending to Braveheart, are just surreal. But others give much food for thought to writers.