The Most Important Basic Grammar Rules to Know Image

Writing is an art. But if you’re not using proper grammar, then it doesn’t matter how beautiful your ideas are—they won’t be understood by your audience.

We know that English grammar can be confusing. Whether you’re a native speaker or are just beginning to study the language, sometimes a little refresher can go a long way.

Basic Grammar Rules

We’ve summarized some of the most important grammar rules and common mistakes to avoid so you can write with confidence.

For more grammar advice, you may also want to check out common grammar myths and mistakes.

Parts of Speech

Nouns and Pronouns

A noun names a person, place, thing, or idea. It can take the singular or plural form.

In the plural form, a change in spelling occurs. In most cases, this change is as simple as adding an -s at the end of a word.

However, for nouns ending in –y, changing to the plural form is achieved by adding –ies.

Additionally, nouns ending in -s, -ch, or -sh sounds will be changed to –es.


  • The fly was caught in the trap. / The flies were caught in the trap.
  • The dog gave me a kiss on my face. / The dog gave me kisses on my face.

Pronouns take the places of nouns. They include “I”, “you”, “he/she”, “we”, “it”, and “they.” As a rule, pronouns must refer clearly to an antecedent (the noun they are replacing).


  • Marvin bought a new phone (antecedent). It (pronoun) sports a high-end software.
  • I love talking with Liz (antecedent), she (pronoun) is such a good listener.

“Who” and “whom” are also a pronouns, though these can be tricky to tell apart, even for grammar aficionados. We have another post where you can learn about the difference between who and whom.


Verbs convey action or a state of being. Every sentence MUST contain a verb to be considered complete. These can include main verbs as well as helping verbs, like “to be” or “to have.”


  • The earth revolves around the sun. (action verb)
  • Jake is walking to the store. (helping verb)

Verbs indicate a tense and can change their form to show past, present, or future tenses.


  • Lila dances every day. (present tense)
  • Lila danced yesterday. (past tense)
  • Lila will dance tomorrow. (future tense)

For correct verb use, you must ensure that the verb and subject agree. While nouns are usually pluralized by adding -s or -es to the end, with verbs it is the opposite: it is the verb in the singular form that ends in -s, rather than the plural form.


  • The child (singular subject) runs (singular verb) to school every day.
  • The flowers (plural subject) smell (plural verb) nice.

Adjectives and Adverbs

Adjectives describe nouns or pronouns, while adverbs modify verbs. One of the most common grammar mistakes is using adjectives when an adverb is needed.


  • She sings good. (incorrect—this is an adjective modifying a verb)
  • She sings well. (correct—this is an adverb modifying a verb)

Many adverbs are formed by adding the suffix -ly to adjectives, or the suffix -able is changed to -ably.


  • large becomes largely; thick becomes thickly
  • amicable becomes amicably; durable becomes durably

You should not drop the –ly of adverbs when used in a comparative sentence.


  • She speaks quieter. (incorrect)
  • She speaks more quietly. (correct)


Commas indicate pauses and can serve many purposes. They can be used to separate items in a list, or to join two clauses with a conjunction such as “and” or “but.”


  • I ate sausages, eggs, and ham for breakfast.
  • It was very hot, but we had to work outside anyway.

Commas also separate nonessential descriptive phrases. If removing the phrase does not significantly impact the meaning of the sentence, commas are used in between.


  • The cat, who has six toes, belongs to my neighbor.

Colons are used to separate a sentence from a list of items, to separate two clauses, or to introduce a long quote.


  • In my bag, I have: one pair of sunglasses, two towels, and my favorite book.
  • There was only one thing left to do: Book the ticket.
  • Maya Angelou once said: “If you don’t like something, change it. If you can’t change it, change your attitude.”

Semicolons can take the place of conjunctions (such as and, but, if) and are often placed in front of introductory words, such as “therefore” or “however.”

They’re reserved for two independent clauses (two clauses that could stand alone as sentences).


  • She was happy to see him; however, she was still hurt.
  • This is absurd; I can’t listen anymore.
  • She’s lived in Los Angeles, CA; Miami, FL; Dallas, TX; and Phoenix, AZ.

Most apostrophes indicate contractions or possession.

The misuse of apostrophes is another of the most common grammar mistakes. Such is the case with its and it’s and whose and who’s.


  • Please don’t leave the door open at night. (contraction)
  • Robert’s hat looks better on me. (possessive noun)
  • Whose dog is this?
  • I’m no longer sure who’s to blame for this chaos.
  • The radio station has lost its license.
  • It’s great to be outside.

Capitalization is also very important. All sentences must start with a capital letter. In addition, all proper nouns (names, titles of books, magazines, movies, and specific places) must also be capitalized.


  • Sarah went to the supermarket and bought her favorite magazine, Writer’s Digest.
  • Have you seen the new Avengers film?
  • Last summer I traveled to France.

Grammar Matters

Writers have the freedom to be creative. However, it is also essential that they master proper grammar if they want to communicate effectively.

Committing obvious grammar mistakes will undoubtedly affect the quality of your written work.

You might end up turning off agents, editors, and even your readers. Make sure you’re writing confidently and error-free by taking time to study the basics.

For quick references, download and print our grammar reference sheet!

Which writing topic would you like us to discuss in our next article? Let us know in the comments below!

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