I agree with your conclusion (this is a worthwhile pursuit), but I have some qualms.
There are a couple of general points that I think really need to be addressed before most of the individual points on this list can be considered seriously:
Following a list of prescriptions and proscriptions is a really poor way to learn any complex skill. A bad writer who earnestly tries to follow all the advice on this list will almost certainly still be bad at writing. I think the absolute best, most important advice to give to an aspiring writer is to write. A lot.
What constitutes "good" writing is a matter of taste. As with other aesthetic endeavors, it's practically impossible to write tasteful prose if you don't have taste in reading prose. I don't see any real way to develop taste without reading a lot, and paying attention to what you're reading and how it's written. To some extent I think every person has to pick apart writing that they think is good and figure out for themselves the nuts and bolts of good writing. The resulting insights might be temptingly easy to distill into bullet points, but this is a very leaky process of abstraction. Most of the value of these insights isn't really communicated in the summary, but is in the data in your brain that made these patterns obvious to you. It's the A Monad is Like a Burrito problem.
Compounding the issue of taste, there's the problem that "good writing" is an underspecified term. There are a lot of extremely popular and wealthy authors whose writing isn't considered "good," at least by those who seem to have taste. Is popularity orthogonal to "good"? Should our goal even be "good," then? Or is maximal popularity not, in fact, our goal? I have no idea what the answers to these questions should be. Would I rather write like Nabokov than like Dan Brown? Yes. Would that be instrumentally useful in spreading my ideas (or ideas that I like) as widely as possible? I don't know. Possibly not.
I have a few comments about specific points on your list, but I'll split those into other comments.
A bad writer who earnestly tries to follow all the advice on this list will almost certainly still be bad at writing. I think the absolute best, most important advice to give to an aspiring writer is to write. A lot.
I believe that was one of the rules on the list.
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?