I mentioned that I'm reading Dorothea Brande, Becoming a riter. Hilary Mantel recommended this book a couple of weeks ago in the Guardian so I searched for it.
As Farhana said, amazing to think it was published in 1934 but reprinted in 1980.
Not so much a how to primer but a deep lesson in observation of your environment and yourself. I've started to carry out some of the exercises and it's interesting how it matches up with some of my daily spiritual practices of mindfulness, silence and being in the moment with focus.
Dorothea Brande, Becoming a Writer, Penguin/Putnam, 1980.