I would recommend the book The Pyramid Principle by Barbara Minto
It covers how to write logically so that a document flows as you have described it.
I've found that the best way to improve my own writing is by practicing writing, editing, and reviewing. Two books that have helped me improve are Stephen King's On Writing and William Zinsser's On Writing Well.
Working at Google, I like that I get the chance to practice through design docs, although that may be my rose-tinted 6-month-tenure glasses speaking. I also try to write outside of work, though the deliberate practice does take some effort for me.
Have you taken the technical writing class at Google? That may be another good resource, although there's a deep waitlist for the ones I see now.
Read well written books. George Orwell, for example, was quite particular about language. Another factor to consider is that brevity takes time. You have keep editing your work to minimise redundancy. After some practice, you will need fewer iterations and eventually some of it will be natural.
Perhaps you will find encouragement here: https://quoteinvestigator.com/2012/04/28/shorter-letter/
Look into technical writing resources. One of the best resources I've seen is from proposal writing classes which you should find common with large consultancy organizations. Also, take a look at military writing guides [1]. There's some quick and simple guidance on writing for brevity and clarity in such guides.
I’ll echo a recommendation which I found productive:
Copy a favorite blog post or a few paragraphs from a book chapter by typing them yourself.
It is a very interesting exercise, makes your brain take in the words and digest them in a different way.
In your case retype one of your coworker’s docs.
Some other sources I’d recommend for this: Seth Godin’s blog, Dan Lyon’s Lab Rats book. Efficient, energetic and energizing writing with a high signal to noise ratio.
You have to think deeply about the topic - certainty about what you are trying to express prevents equivocation.
The structure for the document comes from knowledge of the intended audience and their purpose combined with knowledge of the topic.
Economy of expression is gained from careful and continuous 'refactoring'; restructuring what you say, optimising for simplicity and leverage of the language.
Write early, put it away, come back later, reread it, edit.. rinse and repeat.
Read what you wrote aloud to yourself (go somewhere where people won’t stare at you while you’re doing this)
Listen and try to remember more samples of what you think good writing is, subconsciously your writing will start getting better gradually as you write more.
Your co-workers are keeping a secret. They probably took a lot of time and numerous attempts to prepare a final document with "phenomenal word economy".
Mark Twain (or was it Blaise Pascal?) put it best - “I didn't have time to write a short letter, so I wrote a long one instead.”
I suggest reading more. I've always found that my writing is at it's best when I'm reading more.
Could you give a snippet of your coworker works ?
What you are describing matches perfectly the book "Writing with Style" by John Trimble
He says:
> Books on writing tend to be windy, boring, and impractical. I intend this one to be different—short, fun, and genuinely useful.
See a review: https://nargaque.com/2010/07/07/writing-with-style-john-r-tr...
If you could read only one book on this topic, this is it.