Using Editors Where and When It Counts, Part II: How to Edit Instructions 

When I teach courses on editing, I devote about one-third of the sessions to editing instructions. Why? True, there's always a demand for someone who can edit technical manuals or cookbooks, but my real reason is that working on instructions gets you into editorial shape. It hones your ability to keep readers and their needs always in mind, to weigh each word for accuracy, and to be sure that every sentence means what the writer intends.

Waxman, Maron L. Editorial Eye, The (2003). Articles>Documentation>Editing