https://www.theguardian.com/books/2016/sep/10/my-best-writing-tip-william-boyd-jeanette-winterson
Claire Messud

In fiction, character is (almost) everything. We discuss “the elements of craft” – characterisation, plot, point of view, dialogue, detail, setting, style, and so forth – as if they were separable, as if you could disentangle them one from another. You can’t, of course; but when you filter almost all things through the specificities of character, many questions resolve themselves, almost miraculously.
Each of us is, in any given moment, the sum total of our temperament and experiences up to that point. Our baggage and idiosyncrasies may be suggested in our appearance; but much is invisible to the world. We all know that if there are three people in a room, each will tell a different story about what happened there – so character determines the story itself. But it also determines what will unfold – the plot.
As a writer, when you create a character, you don’t simply create his exterior (the wispy goatee, the receding hairline, the Liberty print shirt and expensive loafers); you must also come to know who he is (bullied in school, uneasy in friendships, veering between eager to please and cruel; vain but pretending not to be), and what has formed him (a Catholic school in the Sydney suburbs? A comprehensive in Exeter? Born with a silver spoon; or things started off comfortably, but his father’s business failed when he was 11? Raised in the shadow of three older siblings? Or alone with a single mum?). You must know his passions (loves pugs? Bicycle racing? First world war history? Talmudic study?) and his fears.
Once you know this person as well as you know yourself (or better), and once you put him, or her, in a particular place in a particular time, your character can only really act (or react) in a limited number of ways. He will notice only certain things, and those things only from a particular perspective; he will interact with others as only he can. If you’re using the first person, or the third person privileging this character, your diction and syntax – your very writing style – will be shaped by this person.
So much about a character is invisible, in fiction as in real life; but what lies beneath the surface will affect every aspect of your story. If you really take the time to figure out who you’re dealing with, much will become clear.
• Claire Messud is a senior lecturer in creative writing at Harvard
