Simplicity is overrated, and a spate of research on "cognitive fluency" and "disfluency" is just starting to put it in perspective. One study that should jar some "plain language" proponents, for example, found that making high-school texts harder to read improved retention. (See http://tinyurl.com/3aouvja) Balancing simplicity and complexity is no simple matter, but science is finally addressing it.
I have a blog on writing—legal writing, actually—and it's the only place I've seen the cognitive-fluency research seriously applied to persuasive writing. Most often, the research is misinterpreted to favor the old plain-language pablum of one-sided simplification. The most persuasive writing doesn't clock in with a low Gunning fog index; consider Darwin's writing style, which is anything but simple—rather, simply excellent. (See http://tinyurl.com/48dxal4)
My blog, "Disputed Issues: Controversies in Legal Writing," is at the link. The advantages of disfluency are discussed at http://tinyurl.com/3e9fqcs; integration of cognitive-fluency research with working-memory research, at http://tinyurl.com/3qz3gxd
[The final link was bad: corrected 7:54 p.m., 8/30.]
I'm jumping in late, but isn't it kind of obvious? Making a high school text harder to read could simultaneously improve retention if you are obligated to read it and at the same time be a bad move for something people must elect to read.
The topics of rationality and existential risk reduction need their own Richard Dawkins. Their own Darwin. Their own Voltaire.
Rhetoric moves minds.
Students and masochists aside, people read only what is exciting. So: Want to make an impact? Be exciting. You must be heard before you can turn heads in the right direction.
Thus, I've decided to try harder and actually put effort into the quality of my writing instead of just cranking stuff out quickly so I can fill in inferential gaps and get to the cutting edge of the research subjects I care about.
That's why I asked LWers for their picks of best nonfiction writing on Less Wrong.
It's also why I've been reading lots of good science writing, focusing on those who manage to be exciting while covering fairly complex subjects: Dawkins, Sagan, Gleick, Zimmer, Shermer, Ramachandran, Roach, Sacks, Hawking, Greene, Hofstadter, Penrose, Wilson, Feynman, Kaku, Gould, Bryson, Pinker, Kurzban, and others.
I've also been re-reading lots of books and articles on how to write well: Keys to Great Writing, Style: Lessons in Clarity and Grace, Elements of Style, On Writing Well, The Classic Guide to Better Writing, The Book on Writing, Telling True Stories, Writing Tools, Ideas into Words, The Chicago Guide to Communicating Science, A Field Guide for Science Writers, Six Rules for Rewriting, Writing, Briefly, and Singularity Writing Advice. (Conversations with Eliezer also helped.)
I don't know if I can become the Voltaire of rationality and existential risk reduction, but it seems worth a shot. Every improvement in writing style is beneficial even if my starry goal is never met. Also, it appears I produce better writing without really trying than most people produce with trying. (If you've ever had to grade essays by honors English seniors, you'll know what I mean.) I expect to gain more by striving where I already excel than by pushing where I have little natural talent.
(I won't try to write everything well. Sometimes I should just crank things out. To be honest, I didn't spend much time optimizing this post.)
My other hope is that a few other writers decide they would like to be the Voltaire of rationality and/or existential risk reduction. May this post be useful to them. It's a list of recommendations on writing style pulled from many sources, in no particular order.
And, just one piece of process advice. Do not apply any of these rules while drafting. Instead, write down whatever horrible shit comes out of you and do it quickly. Then revise, revise, revise.
Now: What are your favorite pieces of writing advice?