Many BAs I coach make the mistake of mixing software capabilities with business rules, employee procedures, and operational guidelines when documenting requirements for an information system or software application.
You may be a great facilitator, an excellent “elicitor” of requirements; your analytical skills may be second to none, but if you can’t package and present information in an easily usable form, then you’re not completing the job as a business analyst.
Vigorous writing is concise. A sentence should contain no unnecessary words, a paragraph no unnecessary sentences, for the same reason that a drawing should have no unnecessary lines and a machine no unnecessary parts. This requires not that the writer make all his sentences short, or that he avoid all detail and treat his subjects only in outline, but that every word tell.