I mostly endorse your list, though I often fail to follow it.

Among my favorites (these are not entirely disjoint from your list, but strike me as importantly different in emphasis):

• Know where I'm going and why I'm going there
  Once I figure out what I'm trying to say, I can say it far more effectively.

• Avoid the second person
  IME, second-person advice is far more likely to inspire defensiveness. When I'm really fine-tuning, I avoid the word "you" altogether unless I'm CERTAIN that my audience will feel complimented by the sentence.

• Present complex points iteratively
  I'm fond of short-phrase bullet points followed by a few sentences of explanation (and cross-references to longer explanations where needed).

• Specify who is doing what to whom.
  This is related to your point 13, though distinct from it.
  Also related is limiting pronoun use.

• Avoid lists of more than five or six items.
  If I genuinely have that many things to say, I try to chunk them into more comprehensive items and expand each item.