The better you can picture something in your head, the better you can write about it.
I’m not exactly sure how this works, but it does. Even if you barely describe an item or a room in passing, the clearer the mental image you have the sharper the interaction – with both the characters and the reader.
That’s not to say that you should start working on the interior décor for your entire world before you start writing. Your first draft should focus on getting the story down and you can fill in details later. But it’s worth bearing in mind. Draw diagrams, if that helps, of rooms and wildernesses (wildernii?) and continents. I can’t draw at all; I’m constantly cursing my inability to set things down in the right order so the lines cross in the right way. But that doesn’t matter. Even the act of trying helps fix these details in the mind.
I think what happens is that you subconsciously slip in details as you then work on the story. People cease to live in a formless vacuum but instead start to interact with their worlds. They pick up case-notes from a paper-strewn desk, for example, rather than from the void. Things happen in a real, solid world rather than a swirling fog of uncertainty. You also avoid mistakes; you cease to cram masses of furniture into a place you’d previously described as small.
Which is not to say that your work should be overloaded with description. On the contrary, it’s vital to be able to slip details in minimally, unobtrusively. Conan Doyle describes Sherlock in one paragraph and then barely mentions his appearance for the rest of the series. Be subtle. Use descriptions to give character and mood rather than to just inform. We never want the old role-playing cliché: ‘The door opens onto a corridor. It is eight feet wide and fifty feet long. At the far end is another door. A pair of orcs are guarding this door. On seeing you they raise their clubs and…’ (I originally said ‘heft their clubs’, which would have been better as the word heft gives an impression of weight and size in addition to the description of the action).
As I’ve been rewriting Australis I’ve come to realise just how little I knew my own world. Although I wanted a functional world of anonymous corridors, I didn’t know well enough where people would be going from and to. And whilst I knew it needed bars – and created some – I had not enough sense of where they were and how people got to them. What might happen outside? So I’ve created a boulevard, an old main drag where shops, cafes and the like will be based. Which in turn gives me a greater opportunity for plot twists and character development and…
This general advice follows equally well for building your characters. The better you know somebody, the more realistically they’ll behave and speak. This is why you see all those ‘character creation templates’ in writing magazines, given out at conferences and the like. You might never need to know that your lead character’s daughter plays the mandolin, but every little detail you add helps them grow as real people in your mind. And the better you can summon up their deep motivations the more rounded they’ll appear on the page.
Which is why I’m going back to the beginning to my next series of rewrites. I’m realising that, whilst they’re far from cardboard clichés, I don’t always know why my characters are behaving as they are. And if I don’t know how am I going to expect the readers to really believe in these people? I’m not saying it’s necessary to know everybody’s deepest neuroses down to the nth degree; I’m too lazy for that. But even the briefest sketch of the major characters will help me draw them better. Then I’ll know how they’ll furnish their apartments and whether they’d be sticklers for order or have that paper-strewn desk upon which is a fine layer of cigarette-ash, disturbed only in one corner where a small envelope lies…