Guidelines are suggestions, not rules.
1) Eliminate all tenses except for the present tense.
2) Eliminate the subjunctive mood.
3) Eliminate the reflexive voice.
4) Replace prepositional phrases with nominative adjectives whenever possible.
5) Eliminate parentheses as much possible.
6) Find ways to get your point across with fewer words if possible.
7) Avoid TMI (too much information): Shy away from off-topic subjects, and unnecessary information even if it is interesting or useful.
8) Eliminate idiomatic expressions if possible.
9) Use "you" whenever possible.
10) Use parallel constructions.
11) Paint verbal pictures to emphasize your message.
12) Be fastidious about the elimination of ambiguity, even to the point of introducing redundancy if necessary.
13) Verify that your text says what you want it to say.
14) Avoid misunderstandings by saying everything that you need to say.
15) Ensure that the reader does not have to work to understand your message, but, at the same time, avoid being repetitious.
16) Preserve the easy flow typical of stream-of-consciousness, conversational, or narrative text.
17) Replace longer words with shorter, simpler, or more common words if not too much meaning is lost.
18) Replace anglicized Greek and Latin words with core English words.
19) Write for your audience. Do not "talk down" to your audience.
20) Use the grammar, spelling, and style that is normal in formal text.