Even if you recognise that what you think of as writing is always actually a writing-reading process, at some point all writers need an external reader. Do other readers get what your inner reader gets? Or do they see things which work against what you're trying to do? Heyer's first reader was always her husband and she would sit tensely watching his face and praying for a chuckle; A A Milne's tribute to his wife was 'She laughed at my jokes' and that's not as callous and self-centred as it sounds, because the connection you have with someone reading writing that you're still intimately involved with is in itself very intimate. So like any other kind of intimacy, you have to choose your partner with extreme care.
One of the first questions, then, is whether you let work-in-progress be read by non-writers. "Why not?" some ask. "It'll be read by non-writers in the end. My sister-in-law is a great reader, and she'll be honest with me." Which may well be true, of course, and indeed your reader needs both qualities. But simple honesty may not be enough. There are all sorts of things which a reader can say of a book which are entirely true, and entirely unhelpful to the writer. Non-writers are rarely expert at disentangling their personal reaction to something in a book from whether or not it actually works as a piece of storytelling, and writers are too thin-skinned, too insecure about the new young piece, to ignore the feedback that they have, after all, just asked for. "I hope it hasn't got more letters in it; I don't like letters in novels," said a non-writing friend, looking at the first page of an early effort of mine. I didn't put a letter in another novel for five years, but guess what The Mathematics of Love is full of?* Whereas another writer is always thinking in the same terms as I am: structure, tension, narrative arc and patterns of imagery. It makes us un-typical readers, of course, and what you discover when you have a great editor is that they can read as readers, but then translate their reaction into something which as a writer we can work with.
So what kind of reading do we want? Needless to say (writers demand no less of readers than they do of themselves) there are different kinds and we want them all. A comment by Mark Dalligan on a piece on the flash fiction site EDF nails it perfectly:
I’m amazed at the range of comments on Greta’s story so far. For me, the complexity of her piece has highlighted different types of EDF reader. I wouldn’t say anyone’s a 100% clear match, we all have elements of each, but interesting nonetheless: 1) Immersive: reads to become one with the action and leave the day job behind. 2) Critical: realises all work has layers and fits into a literary, stylistic and wider societal context. Compares merits and demerits on a stand-alone and contextual basis. 3) Insular: treats a work like an untried dish in a foreign country, looking for what is familiar and basing their opinion on that. May recognise something within limited experience, say tomatoes, but the doubtful looking meat means they miss out on complex spices and more subtle flavourings. Sort of 2D reading.
Immersive reading is like the childhood reading which made us writers in the first place: the one where you lose all sense of time. It's the real magic, and we want to know from readers whether the spell we've tried to cast has worked. One of my best moments on the MPhil at Glamorgan was when the novelist and tutor Catherine Merriman said she'd stopped putting ticks and approving comments on my story 'Maura's Arm' after a couple of pages, and just read. On the other hand what makes a piece 'do it' for you is an un-pin-downable combination of factors often not analysable, even though you may try to rationalise it once you're back in the real world.
Critical reading may or may not be helpful to a writer, depending on what it engages with. It may be true that A Secret Alchemy fits into a particular tradition of fiction about real historical figures, but it doesn't help me get the different stories into the right proportions, or make sure my characters sound medieval without sounding - well, medieval! On the other hand telling me that you didn't believe that X would have done Y is very helpful: I'd better change or amplify X's motivation to make Y convincing, or make him do Z instead.
Insular reading is least helpful of all, but the less experienced the reader, the less capable they probably are of anything else. On the other hand, since the it's probably the way most people read most of the time, if you want to sell books by the pallet-load you should probably take this kind of reading into account. I was amused by the aspiring writer whose comment on 'Maura's Arm' was that he didn't like it because it was just two middle-class people wandering around London for a bit - so what? I knew something of the commenter and wasn't surprised, once I'd got over being annoyed. But if I'd had a comment like that while I was writing the story, goodness knows what I might have tried to do with it - the bomb in the babycarriage, maybe - to suit his tastes. By that time it had won third prize at Bridport so I could laugh. But Bridport, however thrilling, was an external affirmation, while one of the most important things writers have to learn, long before those external affirmations start coming in, is how to protect their own confidence. Learning to choose your readers is perhaps the biggest part of that.
*And I'm sure I'll do it again: apart from the interest of it as a plot device (letters lost, mistaken, never sent, found in the future...), the layers of narrative you get when you embed that kind of thing in a novel are endlessly fascinating.