Steven Pinker puts us on to a new book that sounds maybe even more interesting than Strunk and White, and perhaps even science-based. It is described here
(link)
"There is, however, a species-wide, ancient behavior underlying writing. Cognitive scientists call it joint attention, and we think it is the most sensible and practical place to begin learning to write. In joint attention, two or more people are attending to something, they know they are all attending to it, they know that they are all engaging with each other by attending to it, and they know that they all know all of that. This is home turf for the cognitively modern human mind, which all human beings have had for approximately the past fifty thousand years. More specifically, the cognitive core of writing is “classic joint attention,” in which there are just two people, paying attention to something that is directly perceptible. We never feel any difficulty when we are pointing out something directly perceptible to somebody next to us. We are built for this. We feel at home doing it because the scene of classic joint attention is intelligible by itself. We expect our companion to be able to perceive what we are presenting once it is pointed out.
In order to talk, we blend a complicated mental network, one that often ranges far from home, with a familiar scene—like classic joint attention—so that the foreign network has a domestic anchor. If we make such a blend, and speak from it, our speech becomes intelligible, consistent, coherent, and familiar, even though the speaker is dealing with a diffuse, complex, foreign network of ideas and relationships. The complex network is assimilated to a simple scene through blending.
Consider, as an example of classic style, the following passage from La Rochefoucauld:
Madame de Chevreuse had sparkling intelligence, ambition, and beauty in plenty; she was flirtatious, lively, bold, enterprising; she used all her charms to push her projects to success, and she almost always brought disaster to those she encountered on her way...
"In the scene of classic joint attention, there is something directly perceptible. In contrast, the network of ideas we want to present may not be directly perceptible. The human mind—uniquely among species—is routinely skillful at blending things that don’t naturally go together. In the complex network, the subject may be completely imperceptible. But in the blend, we treat the subject as if it is something directly perceptible. The result is that we can talk about anything at all as if it is directly perceptible: someone’s disappointment or sense of the absurd, a city’s magnificence or a country’s intransigence, a neighborhood’s poverty or a wine’s elegance—all these invisible things and an endless list of others are treated as if they were directly perceptible.
In the mental network of ideas and thought supporting your presentation, the audience may be large and psychologically disposed in a variety of ways. But in classic joint attention, we are speaking to just one other person collusively. So in the blend, we treat the audience like a competent individual who colludes with us to recognize what we are pointing out. In the actual network, the purpose can be anything, or multiple, and conflicting. But in classic joint attention, the purpose is always simply disinterested presentation. So, in the blend, purposes in the network are compressed to presentation....
"There are only two steps to learning to talk this way: (1) think of a scene of classic joint attention; (2) blend it with whatever mental network of thoughts and relationships you confront, and speak from the blend."
So, to write good exposition, one must repair to the classic human experience that pre-exists literacy (a mere 2 or 3 thousand years, and perhaps even orality (50 thousand years), where I point to something and I know you see it too. One must stand in relation to the matter as one would if it were out there in front of us both, like a fish on the beach, or a skewered piece of meat on a stick, something self-evident, real and mutually tangible to two or more people. How do you do this when the "matter" is only in your mind?
One practical thought is that to me, the clearest exposition occurs when the speaker is attending to an object you can see as well (a whiteboard/chalk talk, or a cooking show). When you only have text, or an audio presentation, the ability of the presenter to summon up the referred object--be it a mental model, or a vivid description is the operative factor.
Lately, I've been studying metaphor (Lakoff and Johnson, then Sullivan and Rees) and will soon reinvestigate "story", both by re-reading some of the analytic work and a new book The Story-telling Animal by Gottschall. I'm going to pursue the connections among these three elements (metaphor, shared attention and story) and see what light it can shed on presentations and learning.
Perhaps a book worth reading.
See 
