Google's technical writing course is worth a look
Google's Technical Writing course covers the same ground as general writing advice, but is far more straightforward and nuts-and-bolts. It is structured like a real course, with exercises along the way.
Comedy writers seek the funniest results, horror writers strive for the scariest, and technical writers aim for the clearest. In technical writing, clarity takes precedence over all other rules.
Even experienced editors get the details wrong — the section on active voice is a good example, since it is easy for anyone to misuse.
Ultimately, nearly every rule boils down to one principle: make it more clear.
