Verbs HAS to agree with their subjects.

Never use a big word when a diminutive one would suffice.

Eschew obfuscation.

A writer mustn't shift your point of view.

About them sentence fragments.

As far as incomplete constructions, they are wrong.

Check to see if you have any words out.

Use words correctly, irregardless of how others use them.

Understatement is always the absolute best way to put forth earth shaking ideas. Exaggeration is a billion times worse than understatement.

Don't abbrev.

Don't use commas, which aren't necessary.

Don't write a run-on sentence you have to punctuate it.

Each pronoun agrees with their antecedent.

In a letter themes reports articles and stuff like that we use commas to keep a string of items apart.

It is important to never ever under any circumstances split an infinitive.

Its very important that you use apostrophe's right.

Join clauses good, like a conjunction should.

Just between you and I case is important.

The active voice is preferred. Use of the passive voice is to be avoided.

Watch out for irregular verbs which have crope into our language.

When dangling, don't use participles.

Don't use no double negatives

Don't never use no triple negatives.

No sentence fragments

Corollary: Complete sentences: important.

Stamp out and eliminate redundancy.

All generalizations are bad.

Take care that your verb and subject is in agreement.

A preposition is a bad thing to end a sentence with.

Down with categorical imperatives.

If you've heard it once, you've heard it a thousand times.

Puns are for children, not groan readers.

Who needs rhetorical questions?

Excessive use of exclamation points can be disastrous!!!!!

And, last but not least, avoid cliches like the plague, they're old hat.