Every business professional wants to appear polished, professional and sharp when they represent themselves and the company they work for. That’s why we meticulously choose our attire, business cards and Zoom backgrounds before meeting with clients or colleagues. However, even if you look the part, continually making simple grammatical errors can leave a less-than-stellar impression.

Whether you’re writing a blog entry for your company website, an Instagram post, or an email to a client, it’s important to watch for these common grammar mistakes. We’ll help you figure out how to correct them, and even tell you which mistakes you can leave as is.

Apostrophe Usage

Knowing when and where to use apostrophes can be one of the trickiest grammar rules to master. Most of the time, we actually see professionals use them too frequently. Chances are, you don’t need to use an apostrophe nearly as often as you might think. There are only two instances that require the use of an apostrophe: creating a contraction, such as “can’t” or “won’t,” and showing possession, as in the sentence, “This is the marketing team’s project.”

As a rule, you should never use apostrophes when making a word plural or using a possessive pronoun. For example, many people are tempted to put an apostrophe in the word “its” when using it as a pronoun. Think of the sentence, “The company is in its 30^th year.” Just like other possessive pronouns, such as “his,” “hers,” or “theirs,” “its” does not need an apostrophe. The word “it’s” should only be used as a contraction meaning “it is” or “it has.”

Less vs. Fewer & Over vs. More Than

We’ll admit, the next two grammatical rules are a bit picky, but recognizing these subtle differences between words can lend real credibility to you and your business. First up, let’s clarify the distinction between “less” and “fewer.” These words may essentially mean the same thing, but their correct usage depends on the noun they describe. “Fewer” should be used only to refer to countable nouns – “We had fewer customers today than yesterday.” On the other hand, “less” is used for uncountable nouns – “We’ve had less snow this year.” To make things extra confusing, you should also use “less” when talking about distance, amount, or time: “less than a mile away,” “less than 10% of purchases,” “less than an hour,” etc. Isn’t the English language fun?

Similarly, there can also be confusion about when to use “over” or “more than.” Many people use these words interchangeably to describe something that is above a set limit. In professional writing, though, we recommend only using “more than” in these instances. The word “over” technically means to physically be higher than something else, so using it in place of “more than” may be confusing to your readers.

That vs. Who vs. Which

Like our last rule, many people think all three of these relative pronouns are interchangeable, but there are actually specific times when each is most appropriate. Our first relative pronoun, “who,” is the simplest to place. It should always be used when referring to people or groups of people – “the executive who said,” “the employees who were available,” etc. Any time you are talking about humans, remember to use “who.”

It gets more complicated when deciding between “that” and “which.” Both are to be used when talking about things or objects, but “that” should only be used in restrictive clauses, while “which” is the better choice for non-restrictive clauses. An easy way to identify a non-restrictive clause is to look for commas. Non-restrictive clauses are typically contained by commas, and without the clause, the sentence would still be complete. “We discussed the changes to the marketing plan during the meeting, which was on Tuesday,” is an example of a sentence with a non-restrictive clause. On the other hand, restrictive clauses do not use commas, such as the clause in the sentence, “This is the only promotion that will work.” In either case, if the clause does not add essential details to the sentence, consider dropping it completely to keep your writing simple and easy to read.

Hyphen Usage

Another common error we see in professional writing is overusing hyphens. In general, hyphens should be used only when two words are combined to describe a noun that comes directly after. These two-word combinations, such as “open-minded” or “part-time,” become compound adjectives, and the hyphen lets the reader know the words work together to create meaning. If the two words come after the noun they describe, they do not need a hyphen. For example, you may have a pet-friendly office, but your office is pet friendly.

Now that we’ve spent a smooth 700 words talking about how important it is to avoid grammatical mistakes, let’s talk about a few instances when it’s okay to loosen the rules and make some errors.

Passive Voice

This may be a slightly unpopular opinion, but as long as passive voice isn’t overused, we think the occasional passive sentence is okay. When writing a longer article or story, sometimes a sentence with passive voice will simply flow better and sound more natural. Other times, you may want to emphasize the action in a sentence, rather than the person doing the action. Consider the sentence, “The CEO was elected yesterday.” In this case, it makes sense to draw more attention to the act of electing the CEO than the unnamed board of directors who voted them in. Of course, it’s generally still preferred to use active voice when possible, but if sticking with passive makes your point easier to understand, go with your gut instinct.

Run-On Sentences

In school, we all learned about the horror of run-on sentences. It’s true, if your entire email or blog post is made up of lengthy, winding sentences with no punctuation, it will be hard to read. However, we would also argue that using only short sentences free of adjectives or any other description is not particularly interesting. The best writing balances both short and long sentences to keep readers engaged while clearing making a point. When you do need to write a longer sentence, don’t forget to use commas, em dashes, and other punctuation appropriately to break up clauses and keep it easy to read.

Conversational Writing

For many business professionals, most of their daily writing is short-form and fairly casual. If you’re shooting off a quick email to a colleague or writing a social media post based on a popular meme, your readers will probably not care that you included unnecessary adverbs or used slang. In these instances, it’s acceptable and even recommended to write how you would naturally speak, rather than with textbook grammar. Just be sure your spelling and overall word usage is still correct. The online trolls won’t hesitate to mock you for using “their” instead of “there.”