Grammar defines how sentences are put together and how your brain parses the information to be understood. Unfortunately, English is one of the most confusing and complicated languages in the world, and oftentimes it seems as if there are many more exceptions than rules. Nevertheless, correct grammatical knowledge remains an important part of writing well.

Most people will fall into the habit of making the same mistakes over and over again to the point where they don’t even realize that what they’re doing is wrong. Widespread incorrect usage encourages this. Below is a quick and dirty guide to some of the most common mistakes. Get these right and you’ll be well on your way to writing better!

Kiri’s Pet Peeves


When spoken, some contractions, such as should’ve, could’ve, and would’ve, sound like “should of,” “could of,” and “would of.” It is important to remember that this is incorrect. The contractions are for “should have,” “could have,” and “would have.” You don’t could of. You could have.


  1. He should have known already, but a poor memory was among his many faults.
  2. She couldn’t have done anything about it, but she felt horrible all the same.


Commas are used to offset direct address and should be included on either side of a direct address unless another punctuation is already in use. A direct address does not have to be a proper noun and can be any word or words used in place of one.


  1. Hey, Sammy, what are you doing here?
  2. I didn’t do it, you paranoid maniacs!
  3. Biscuit, I hate you.

Conversational Comments

Commas should offset words and phrases such as yes, no, well, why, now, etc., or oh.


  1. No, he didn’t much care for the taste of rabbit.
  2. Yes, I don’t see why not.
  3. Public humiliation, wrath, bodily injury, torture, etc., may result from failure.

Confirmatory Questions

Confirmatory questions are preceded by a commas.


  1. So you understand now, don’t you?
  2. This is where everything goes, right?


Always place commas and periods inside quotations. Always place colons and semi-colons outside quotations.


  1. “Please don’t kill me,” she pleaded quietly.
  2. He had quite a long list of “offenses”: breathing, drinking water, talking, and so on.

Question marks and exclamation points go inside quotations when they are part of the quote, otherwise, outside. When both the quote and its context are questions or exclamations, place the punctuation inside the quotes. Never end in double question marks or exclamations.


  1. “Can you remember that?” she asked with a sigh.
  2. Who was it that had said, “I’ll kill you”?


Semicolons separate complete sentences. If you do not have a complete sentence on either side of your semicolon, then you’re using it incorrectly! Additionally semicolons are used to list items that contain commas within them.


  1. He hated the forest; it was filled with too many bad memories.
  2. She had been to many places: a bright, sunny field of sunflowers; a cold, empty desert where nothing would grow; and of course, this place, this snowy plain that stretched on for miles.
  3. Please don’t misuse semicolons; that would make baby Godzilla cry, which would probably result in something exploding eventually.

Common Comma Mistakes


Nonrestrictive appositives are short phrases that further elaborate a subject. Sometimes, appositives start with or, such as, particularly, especially, and similar words. Appositives can also be used to identify or explain a preceding name. They should be offset by commas. Adjectives in “appositive position” should also be offset in commas.


  1. It was a miserable day, rainy and cold, but she had decided to venture out regardless.
  2. His grandmother, a wise and cunning old hybrid, had died of natural causes at the impressive age of sixteen.
  3. Pain and suffering, particularly the kind that comes from disobedience, was not something he remembered fondly.

Adverb Clauses

The following subordinate conjunctions begin adverb clauses: after, as long as, as soon as, as far as, in order to, unless, where, even though, so that, provided, because, as if, lest, wherever, before, in case, wherever, until, as though, than, while, if, when, whether, though, although, since, as. All introductory adverb clauses are followed by a comma.


  1. As long as he could still see, everything would be all right.
  2. While he sat there, he pondered all the usual questions of life, death, and mortality.

Adverb clauses that end a sentence do NOT need a comma unless they begin with though, although, as, or since (and only if “as” or “since” mean “because”) Note that clauses beginning in because don’t need to be preceded by a comma. Weird, huh?


  1. The cake is a lie unless you’re dead. (Notice! No commas!)
  2. He didn’t understand anything at all, since he hadn’t been there in the beginning.
  3. She couldn’t stand him because he was too talkative. (Notice! No commas!)

Contrasting Expressions

Contrasting expressions are often introduced with not, but not, though not, unlike, and similar phrases. They should be set off by commas.


  1. He considered most things, but not all things, to be rather trivial in the end.
  2. It had been from her father, not her mother, that she had gotten most of her characteristics from.

Long Introductory Phrases

Commas should offset introductory phrases of four or more words. Short introductory phrases do not need to be offset unless there is a chance of misreading.


  1. In an effort to change himself for the better, the coyote had decided not to start fights anymore.
  2. In the summer, time flew too quickly.
  3. Because she hadn’t known about it beforehand, she couldn’t have stopped herself from appearing tactless.

Nonrestrictive Adjective Clauses

Adjective clauses begin with who, whom, whose, which, and occasionally when or where. “Nonrestrictive” dictates that the clause does not answer the question of “which one.” If it does, don’t use commas.


  1. His friend, who had always been most trustworthy, had finally lied to him.
  2. The girl who he had seen the day before would not leave his mind. (Notice! No commas!)
  3. The library, which was crumbling in many places, had become her favorite haunt.

Nonrestrictive Participle Phrases

Participial phrases begin with verbs in the present active participle form (verbs ending with “-ing”) and should be offset with commas. “Nonrestrictive” once again dictates that the phrase does not answer the question of “which one,” in which case commas are not needed.


  1. Marshall, speaking rapidly, described all the details of his scouting venture.
  2. The wolf running rampant over the snowy dune did not notice the bear just beyond the forest clearing. (Notice! No commas!)

Introductory Participles and Participial Phrases

These are automatically followed by commas. Once again, participial phrases begin with verbs in the participle form (“-ing”).


  1. Having woken up later than usual, he had missed lunch and was thus finding his stomach incredibly disagreeable.
  2. Frowning, he decided to come back later.

Coordinate Adjectives

Coordinate adjectives are adjectives used to modify or describe the same noun. The individual adjectives should all be separated by commas, but there should be no comma between the final adjective and the noun. Coordinate adjective phrases follow the same rule.


  1. The tall, muscular werewolf looked to the sky.
  2. It was a sturdy, brown, and very worn desk, but it was still rather usable.
  3. He was a smart, inquisitive young lad, and she was rather fond of him. (Note that “young lad” is treated as a noun phrase here, rather than a separate adjective and noun.)


Homophones are words that sound the same but are spelt differently and have different meanings. This is something that’s continuously addressed in grade school, but that many, many people still have issues with well into their adult lives. Some of the most common swaps are below.


They’re is the contraction for “they are.” There is a location and contrasts with “here.” Their is an androgynous, plural possessive pronoun.

Example: They’re bringing their bows and arrows over there to shoot some people.


It’s is the contraction for “it is.” It is NOT the possessive. Its is the possessive pronoun.

Example: It’s moving its young to the other side of the burrow.


Accept is to consider or to hold something true. It also means to willing receive something being offered. Except is a preposition meaning to exclude.

Example: You may accept everything being offered except the vodka.


Then is used to indicate time. Than is used to compare things.

Example: He ate some pie, and then he ate some more, so much that he ended up eating more than me.

Other Mistakes


To lay is to place or set down and takes a direct object. To lie is to recline and does not take a direct object.


  1. She laid the book back on its table.
  2. They had spread out under the stars and were lying there contentedly.