“A tenet of journalism is that “the reader knows nothing”. As tenets go, it’s not flattering, but a technical writer can never forget it. You can’t assume that your readers know what you assume everybody knows, or that they still remember what was once explained to them.
The principle of scientific and technical writing applies to all nonfiction writing. It’s the principle of leading readers who know nothing, step by step, to a grasp of subjects they didn’t think they had an aptitude for or were afraid they were too dumb to understand.”
– William Zinsser