Top 10 common grammar mistakes to avoid for student success

College students should avoid making common spelling and grammar mistakes when writing a research paper. A small mistake with an easy word will make your paper look sloppy and unorganized, and your teachers will wonder how accurately you researched the rest of your paper (and how you’ve gotten away with making these mistakes for so long!). Follow these 10 simple tips for college research papers.

Knowing proper grammar will keep you from making mistakes. (Credit:

Knowing proper grammar will keep you from making mistakes. (Credit:

“We’re big advocates of conversational writing that’s engaging, persuasive, and fun.… On the other hand, making some grammatical errors just makes you look bad, and hurts your effectiveness. Sometimes we even misuse words simply because we hear others use them incorrectly,” explained Brain Clark in “15 grammar goofs that make you look silly,” on CopyBlogger. Take a look at our list of top 10 grammar mistakes below.

Avoid the grammar police

1. Its versus it’s. “Its” is the possessive for something belonging to the pronoun “it.” A good way to remember is that other possessives like “hers” and “yours” also do not have apostrophes. “It’s” is the contraction for “it is” and “it has.” Whenever you’re confused, replace your “its” with “it is” and see if it makes sense in your sentence. For example: “The dog tipped over its water bowl.” If you say, “The dog tipped over it is water bowl,” it doesn’t make sense, so don’t use an apostrophe.

2. Your versus you’re. Similar to its. “Your” is the possessive belonging to you. “You’re” is the contraction for “you are.” Again, try each in a sentence to see which makes sense. It also really helps me to say it out loud to myself.

3. There, their and they’re. “There” is a direction (here and there). “Their” is the possessive for they, something belonging to them. “They’re” is the contraction for “they are.” Here’s a sentence to keep all three words in perspective: “Over there is their dorm that they’re walking to.”

4. Who versus whom. Use “who” when you are referring to the subject of a clause and “whom” when you are referring to the object of a clause. “If we think about people, the subject of the sentence is the person doing something, and the object of the sentence is having something done to them,” explained Mignon Fogarty, a.k.a. Grammar Girl, in “Who Versus Whom,” on Quick and Dirty Tips posted March 9, 2007.

To decide which to use, answer your question with the word “him.” “I gave it to who/whom?” “I gave it to hiM.” The m in him (the object) tells you to use the choice with “m”—whom. “Who/whom stepped on the bug?” “Him stepped on the bug.” Him (the subject) makes no sense, so use the choice without “m”—who.

5. Then versus than. “Then” means at a point in time: We had class then went to lunch. “Than” is used to compare things: Apples are bigger than grapes.

6. Could’ve versus could of. There is no “could of” and there never will be. Could have, would have and should have are the proper terms and can be made into the contractions could’ve, would’ve and should’ve.

7. Compliment versus complement. “Compliment” is praise and can be used as “You look hot today!” “Complement” means balance or counterpart and is used as “jelly complements peanut butter.”

8. Literally. English uses a lot of metaphors and figurative language. Don’t say, “It literally scared to me death.” You’re not actually dead. And don’t use literally in place of “very” or “seriously”: “It’s literally ten feet tall.” Ten feet tall is not a figurative phrase. Use literally only if your statement is absolutely true: “He literally cried over spilled milk when the liquid shorted out his laptop.”

9. Capitalize “Is” in a title. When capitalizing all the major words in a title or headline, don’t forget to capitalize the word “Is.”This might be the most common mistake people tend to make, yet never had any idea…until now. All verbs, nouns, adjectives and adverbs are capitalized, as well as the first and last words. “Is” is a verb and should be capitalized.

10. Spell check versus synonyms. Sure, a spell check can find and fix your typos. But it can’t tell you whether you should use “stationery” or “stationary,” “counselor” or “councilor,” “principle” or “principal.” When in doubt, use the thesaurus feature in your spell check.

In today’s fast-paced electronic world, sending someone an email or text is a quick click away, but it’s easy to make embarrassing mistakes (even I’m guilty of it!). Nate Fanaro is a programmer who created a Twitter grammar bot. “When I write an email, I read it over and over and over before I click send. …And I think that’s something we could all keep in the back of our minds,” Fanaro said in “Dear Grammar Bot Guy: Your Annoying” posted by Caitlin Dewey in Winnipeg Free Press, December 16, 2012, found on (P.S.: Did you notice the grammar error in the title of this article?!)

To learn more, check out the follow-up article “10 more common grammar mistakes to avoid.”

For more grammar, punctuation and synonym rules, check out Questia’s Language and Linguistics page.

Do you take the time to proofread your writing before you click send?

9 replies
  1. Nita says:

    It is, indeed, almost incredible but true that many people think ‘could’ve’ means ‘could of’ instead of ‘could have’. This is mainly, I think, because basic grammar is no longer taught in schools. However, should it not have been pointed out that although ‘could have’ can be contracted to ‘could’ve’ in an informal note or letter, it is certainly not permitted in an academic essay.

  2. Larry (Lorenzo Bernardotto - It.) says:

    Well … I usually check twice, three, four times my writings before “click send”. But mistakes are always present, due to I’m Italian and I learnt English as a self-taught at home. Thus, please, pardon me! I never attended an English course. I fight my battle every day about the English language.

  3. Kristin says:

    These probably don’t warrant spots in the top ten, but:

    A lot vs. alot (which is not a word) and
    Myriad vs. myriad of. Myriad basically means “a lot of” so “myriad of” = a lof of of

    Thanks; great list!

  4. laurie Augustine says:

    This is good advise. Grammar changes over time. You can now say “But” instead of “However” at the start of sentences. However what you said is good advise. I check several times but sometimes still miss a mistake.

  5. Judson Reos says:

    It s especially important if you re looking for a job or trying to impress a new client. In this infographic, GrammarCheck has collected a list of some of the most common grammar errors people make and how to avoid them.

    • Nicole Reinard says:

      That’s a great point, Kate! It depends on the situation. For example, disorganized applies to the type of person who stuffs receipts into the sock drawer or can never find car keys. Unorganized applies to things which have not yet been arranged in an organized manner. Based on this reasoning, a person would be disorganized, but an office would be unorganized.

  6. Lance says:

    I was using But at the beginning of a sentence, like However, and was getting called out on it by this old instructor I had last year. This and other things made me call her the granny nanny. Now I thank you for pointing out that grandma, error I mean, grammar, has to evolve.


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