For the last couple of weeks I’ve been absorbed in rewrites of my next novel. It’s not the first set of revisions, and perhaps my writing process is unusually inefficient: it’s not until the second draft that I’ll share the work-in-progress with a couple of trusted writer-readers, then the third draft goes off to my agent, and comes back for more (thankfully, relatively minor) amendments.

Writing is hard: all writers say it (sheepishly, because it’s not like we’re working down a coal mine). And some days, rewriting is the hardest thing of all. Every word, every sentence, has to be hauled up from the deep, to lie motionless on the page – if not dead, then at least in a critical condition. I worry that if I’m boring myself I’ll certainly bore the reader; I know every word will have to be rewritten yet again. But as I tell my students, you can’t rewrite a blank page – so there’s no choice but to carry on.

When it’s a slog like this, when everything I write seems flat and awful, that’s when I find myself wondering if it’s too late to retrain as a gardener or a dog-walker. Something useful and energetic, with plenty of fresh air.

But then … then I reach a part of the book where it’s like I’ve remembered all over again how to write. And the difference is in the unexpected. It’s about whether or not I’m surprising myself – with the turn a conversation takes, or a connection I hadn’t known was there, or just a sentence that has energy and voice, that seems to write itself rather than lurking around half-formed until I clumsily patch it together.

This is why some writers prefer not to plan their novels at all: knowing where they’re meant to be going takes away the sense of adventure and the joy of discovery. If you know what you’re going to write, what’s the point in writing it? And even though I’m a planner, I still need that sense of unexpectedness. Making minor changes to a scene may seem more efficient than rewriting that scene from scratch, but I’ve realised it’s actually harder and more time-consuming – because if you’re tinkering round the edges of something that already exists, there’s less room for surprise, less pleasure in making something fresh and new and alive.

And as with most things I learn about writing, I’ll forget this – and have to discover it all over again when it’s time to rewrite the novel after this one.