Twelve Deadly Sins: Some Editing Advice
For more advice, check out Purdue University’s Online Writing Lab or OWL at http://owl.english.purdue.edu/handouts/grammar/index.html.

After you have finished revising your composition and are pleased with content and structure, it’s time to edit. Pay attention to the language as language – to grammar, usage, mechanics, and sentence style. At the very least, look out for these twelve deadly sins.

1.    Left-out, Doubled, and Unnecessary Words
First, read your work aloud to see if you have left or unnecessarily repeated words words and phrases. Second, delete these, and similarly mountainous, words: very, a lot, really, quite, beautiful, marvelous, awesome, considerably, basically, sort of, kind of, definitely, somewhat, . . .
2.    Fragments
Make sure that every sentence has both a subject and a predicating verb. Unlike this one. A sentence always contains at least one independent clause. Exception to the rule: If you’re writing informally – fiction, perhaps, or a personal essay – and you wish to use fragments for effect, you may do so as long as you’re in control. Beware.
3.    Run-on (or Fused) and Comma-spliced Sentences
Run-on and comma-spliced sentences result when independent clauses are joined without adequate punctuation. A comma alone cannot join two independent clauses.

Run-on or fused sentence: I love playing Frisbee it’s competitive without being cut-throat. Corrected: I love playing Frisbee because it’s competitive without being cut-throat. OR I love playing Frisbee. It’s competitive without being cut-throat. OR I love playing Frisbee, which is competitive without being cut-throat. OR I love playing Frisbee; it’s competitive without being cut-throat.

Comma-spliced sentence: Many trains speed through downtown Bell Buckle every day, happily, they always blow their whistles to announce their arrival. Corrected: Many trains speed through downtown Bell Buckle every day; happily, they always blow their whistles to announce their arrival. OR Many trains speed through downtown Bell Buckle every day. Happily, they always blow their whistles to announce their arrival.
4.    Sentence Sprawl (Loose or Rambling Sentences)
Word order in English determines meaning. There is a world of difference, for instance, in the meaning of these two sentences: Agatha scratched the dog and The dog scratched Agatha. Because word order is so important, sentence length is also important. To make sure your reader understands your sentences, you would be well advised to pay attention to word order and to control the length of your sentences. Awkward: Jim the Boy is about a little boy who is ten and has no father and only a mother and several uncles, three to be exact, to take care of him in the mountains of North Carolina where they live. Better: In Jim the Boy, set in the North Carolina mountains, a ten-year-old, fatherless boy lives with his mother and three uncles.
5.    Faulty Agreement
A. Subjects and predicating verbs must agree in number. Incorrect: Alexander was one of the students who was assigned work crew on Saturday. (In this sentence, the word who refers to students, not Alexander.) Correct: Alexander was one of the students who were assigned work crew on Saturday.
B. Verbs must agree in tense. Incorrect: Jim’s uncles woke him up to see the arrival of electricity. When the lights suddenly come on, they all applauded. Correct: Jim’s uncles wake him up to see the arrival electricity. When the lights suddenly come on, they all applaud.
C. Pronouns must agree in number and person with the nouns or pronouns to which they refer. Incorrect: Each student must remember where they put their backpacks on the way to Chapel. Correct: Each student must remember where he or she put his or her backpack on the way to Chapel. OR All students must remember where they put their backpacks on the way to Chapel.
6.    Faulty Parallelism
Similar sentence elements, like items in lists and comparisons, must be written in the same or parallel grammatical forms. Incorrect: She is likeable because of how smart she is and her sense of humor. Correct: She is likeable because of her intelligence and her sense of humor. Incorrect: He has a face like a pig. Correct: He has a face like a pig’s.
7.    Misused or Missing Commas
Commas are not powdered sugar; sprinkled liberally, they actually make the writing taste sour. Use them sparingly.

A.  A comma must be used to join independent clauses in a compound sentence. The comma comes before the coordinating conjunction ("and," "but," "for," "or," "so," "nor," and "yet") when the conjunction joins two independent clauses. Incorrect: We read Jim the Boy and we wrote essays about Tony Earley’s voice. Correct: We read Jim the Boy, and we wrote essays about Tony Earley’s voice.

B.  Items in a series are separated by commas.

C.  Sentence-openers are followed by commas. Examples: Afterwards, we ate dinner. In fact, whenever we go to the theatre, we eat dinner afterwards. Even though we had eaten a little something before leaving home, I was hungry by the time the show ended.

D.  Nonrestrictive phrases and clauses are set off by commas. If a clause or phrase (like an adjective clause or an appositive phrase, for example) is not necessary to the basic meaning of the sentence, then it is considered to be "nonrestrictive." Such phrases and clauses are marked off from the sentence with commas.

Examples:
Santa Claus, a jolly, fat man, visits my house every year in December. BUT A jolly, fat man named Santa Claus visits my house every year in December.
The Webb School campus, located on a hill near the center of Bell Buckle, is leafy and green. BUT The campus located on a hill near the center of Bell Buckle is leafy and green.

Restrictive phrases and clauses are those absolutely necessary for the basic meaning of the sentences in which they appear. Restrictive phrases and clauses are not accompanied by commas.

Interjections (like "okay" and "hey"), dialogue, direct address ("Thank you, Mr. Smith"), ad interruptions (words like "well" and "as a general rule") are set off by commas.
8.    Misused or Missing Apostrophes
The apostrophe signals possession or the absence of a letter in a contraction. Do not use the apostrophe and an "s" for the plural of a noun.

Incorrect: My parent’s are always mad at me. Correct: My parents are always mad at me.
Incorrect: The dog is licking it’s foot because its injured. Correct: The dog is licking its foot because it’s injured.
9.    Misplaced and Dangling Modifiers
Put modifiers as near to the words they modify as possible. Remember that if a modifier precedes an independent clause, it automatically describes the next noun or pronoun, whether you mean it to or not.

A misplaced modifier has not been put where it belongs; as a result, the meaning of the sentence is unintentionally ambiguous. Incorrect: Mr. Smith read an announcement about students’ uniforms in Chapel. Correct: In Chapel, Mr. Smith read an announcement about students’ uniforms.

A dangling modifer appears to modify the wrong word or a word that isn’t in the sentence. Incorrect: Having changed the sheets and straightened the bedcovers, the room looked much neater. Correct: Having changed the sheets and straightened the bedcovers, Elizabeth thought the room looked much neater.
10.    Vague, Stilted, Clichéd, or Flowery Language
Don’t try to sound older or more educated than you really are. Write directly. Keep asking yourself what you’re trying to say and say that. Sounds simple but it isn’t. Poet Robert Frost said that the adverb is the enemy of the verb and the adjective the enemy of the noun. Sentence muscle is found in the subject-verb relationship: write with specific concrete nouns and active verbs.
11.    Vague Pronouns
Every pronoun must refer to or replace a specific, previously stated noun or pronoun. (This preceding noun or pronoun is called the antecedent.)

Incorrect: School is hard these days, especially with the end of the quarter coming. It makes me feel nervous. (What "makes me feel nervous"? School? The "end of the quarter"?)
Correct: At the end of the quarter, school becomes hard, and I feel nervous.

Quick Fix: Circle every "it" or "this" and make sure you can find the antecedent. If you can’t, you’ve got a problem.
12.    Passive-voice Verbs
Verbs not only have tense or time markers; they also have voice – active and passive. Writers prefer the active voice because it results in a clearer, more direct, and more concise expression than that produced by the passive voice.

In the active voice, the subject of the sentence is the actor: "Leslie threw the tennis ball over the net." "Leslie" is the actor in the sentence. In the passive voice, the subject of the sentence is acted upon: "The tennis ball was thrown over the net by Leslie." The "tennis ball" can’t act alone; it is receiving the action done "by Leslie."

Quick Fix: Circle all forms of the "to be" verb (is, are, was, were) and try to eliminate as many as you can.