Prepositions dangle awkwardly if you use them to end sentences with.
Avoid cliches and colloquialisms like the plague, or you will seem old hat.
Employ the vernacular, while eschewing arcane and obfuscatory verbiage.
Avoid ampersands & abbreviations, etc.
Take it easy with parenthetical remarks (however relevant), to avoid chopping up sentences (unnecessarily (we might add)).
To ever, however artfully, split an infinitive, marks you as grammatically challenged.
Skip the foreign words and phrases you know, n'est-ce pas?.
"I hate quotations. Tell me what you know." --Ralph Waldo Emerson
Comparisons can clog up writing as badly as alliterations and cliches.
Avoid redundancy and verbosity, or readers will think you are repeating yourself and using too many words as well besides.
We really get @*&%$**)!! when you use vulgarities.
Clear, specific writing beats vagueness, we suppose. Whatever.
Overstatement totally destroys any credibility you ever had forever.
Understatement can, at times, perhaps shade a point to the point of its fading away.
One word sentences? Eliminate.
Analogies work about as well as fur on a flounder.
"Is" just sits there. Pick verbs that do something.
Even if a mixed metaphor sings, you should derail it.
Who needs rhetorical questions?
Its distrakting too punctuat, an spel rong.
And from John V. in Denver, "Don't Verb Nouns."