Conflict
Writing in organizations is complicated by the fact that an organization is volatile, i.e., changing all the time. Sometimes change is predictable, other times it's unexpected. But in any event, accepting change, appreciating change, is essential. Again, your messages should reflect this sense that change is productive. Change, of course, involves creative confusion, recognizing and deciding between courses of action. You feel pressure to select one option over another. Writing situations, in short, can come to you in the form of a double bind.
Dialogue
Change is social: it takes place because other people are involved with, invested in, the team, the group dynamic. So, write as if you're in a conversation, not "monologuing," which means finding a reader-friendly voice. In particular, it involves foreseeing reader queries, doubts, resistances, etc. Plus, making the reader feel part of any decision-process shows respect. It "flattens" the writer-reader connection. "Inclusiveness" is a form of courtesy.
Empowerment
Conversation can be achieved in several ways, but one thing to keep in mind, stylistically speaking, is "write it like it talks." In other words, don't fall back on overly formal business clichés. Don't say: "As per your request of the 16th instant...." And don't rely too much on abstractions such as "company policy." (Note: often, company policy is invoked to exclude, intimidate a reader, as in "company policy forbids....") Seek to "raise" your reader by focusing on what can be done, not just what can't. Write as if you respect your reader's knowledge and trust his/her judgment.
Open-endedness
Effective business communication involves open structures, not closed. That's why the final words of a business message usually suggest some kind of follow-up action. A sales message creates opportunities for further contact. ("Phone our 800 number today"; "Check out our website"; "Test drive the latest Rann-9000 tomorrow"). An effective job application/covering letter ends with a request for an interview. A report concludes with a recommendation (or list of recommendations).