Make Three Assumptions
If you doubt that it's largely common sense, let me give you three assumptions that you can safely make, whatever you need to write. Keep them firmly in mind, and you will avoid virtually all the major blunders that can destroy the effectiveness of a piece of writing:
1. Your reader has better things to do
These days everyone has too much to do and too little time. So you need to picture your reader sitting at a desk piled high with paper, sandwich in hand, and an inbox bursting with unread emails.
How will this mental image affect what you write? For starters, it means you urgently need to compete for your reader's attention, from your very first sentence; no lengthy preamble building up to your killer argument on page 4.
It means that being boring is the second worst crime your writing can commit (we'll come onto the worst in a moment). For an example of how not to do it, look no further than this headline from a glossy corporate ad I saw recently: "Strategic partnerships bring innovative new perspectives." Frankly, I'd rather gouge out my eyes with a spoon than read on.
And it means you can't afford to waste your reader's time by telling them what they already know, or exactly what they would expect to hear. Let me know, for example, if you come across a major law firm that doesn't claim to offer its clients "pragmatic commercially focused business solutions".
2. Your reader is not an idiot
Yes, forgetting this is the very worst crime a writer can commit. Bad writers do it all the time. They attempt to use words to conceal the obvious truth; they make absurdly exaggerated or unsupported claims ("simply the best"); they use redundantly elongated verbal formulations, in the mistaken belief that it makes what they are saying sound more important; they talk down to their readers.
For example, how about the flyer shoved through my letterbox the other day by a local estate agent, offering me "a FREE valuation, at a time to suit my convenience"!!!? How stupid do they think I am, to imply that the fact they don't charge for carrying out valuations is some kind of amazing special offer?
Your reader may lack knowledge, but you should always assume that they possess intelligence - and that they will react just as you would if they feel their intelligence is being insulted. True, you may sometimes get away with patronizing, bluffing or misleading your reader. But the risk is too great. Because if the reader sees through you, your chances of establishing a rapport and building a relationship of trust are less than zero. And when writers lose the trust of their readers, they lose everything.
3. Your reader will always read between the lines
Think, for a moment, about how you read. It's an active process, isn't it? You don't simply soak up information or ideas from the words on the page, like a sponge absorbing water. You interpret them; you look for hidden meanings and secret agendas; you test them against your own understanding of the world. And there's a little voice inside your head that constantly comments on what you're reading and saying: "Hmm, I suppose there is (etc.) "
Understanding that what takes place between writer and reader is a dialogue, not a monologue, has enormous implications.
Consider, for example, this sentence from a well-known design consultancy's website: "We're still hopeless at pack design." Terribly negative, I think you would agree. Except that, in context, it's fantastically positive. It comes towards the end of a section in which they list their areas of strength. They are, apparently, very good indeed at all types of corporate literature, pretty hot at web design, excellent at annual reports ... but still hopeless at pack design.
Just when we're expecting an unbroken catalogue of success, we get a bracing blast of candid self-criticism. It's totally disarming! We find ourselves thinking: "These guys must be fantastic designers to get away with that!"
Of course, I'm not suggesting that you should try to pull off the same trick in your next new project proposal, report or feasibility study. But what we see here is how, in the most engaging writing, the reader actively participates by supplying the writer's true meaning. And just about all the things that add "color" to writing - metaphors, simile, understatement, and wit of all kinds - depend on this kind of collaboration between reader and writer.
Which is why I'm uncomfortable with that conventional wisdom about good writing always direct and to the point; quite often, the scenic route is a better way of reaching your destination.