After working with copywriting clients for over a decade, quite often I am asked to go back to the basics. Clients ask me questions about grammar and punctuation rules for writing all the time! This inspired me to write this easy, handy guide on grammar and punctuation rules for writing wonderful web copy! 

In addition to grammar rules, I am also including some best writing practices involving common mistakes that I see. Bookmark this blog and keep it on hand as a reference sheet. And as always, feel free to reach out if there is something that I didn’t cover here!

Commas (,) 

Commas might be the very most common question that clients ask me about. Does this sentence need a comma? How many commas are too many? And don’t forget about the Oxford comma–you’re either a fan or you’re not. 

After an Introductory Word or Phrase

Use a comma after words like ‘Well,’ ‘Oh,’ ‘Yes,’ or after a phrase that starts a sentence. For example, “Yes, I would like to research a new list of blog topics.” 

In a press release, use a comma when you are writing a quote before introducing the speaker. For example, “This copywriting company helped me make $100,000 from a single weekly marketing email,” says Jane Done, Owner of ABC Company.

Listing Items

Use commas to separate items in a list. For example, “I have to update Facebook, Instagram, and LinkedIn today.” When listing three or more items, put a comma before ‘and’. 

Separating Clauses

Use a comma to separate a small side idea from the main idea of the sentence. For example, “My intern, who will graduate this spring, is great at making Instagram reels.”

In Dates and Addresses

Use commas to separate the parts of dates and addresses. For example, “She was born on July 4, 2010, in New York City, New York.”

oxford comma

A Note About the Oxford Comma

The Oxford comma, also known as the serial comma, is a punctuation mark used just before the conjunction (like ‘and’ or ‘or’) in a list of three or more items. 

Its purpose is to prevent confusion and ensure clarity in sentences. For example, in the list “apples, oranges, and bananas,” the Oxford comma is the one placed after “oranges” and before “and.” Without it, the sentence might suggest that oranges and bananas are somehow grouped together differently from apples. 

While some style guides recommend using the Oxford comma for its clarity, others omit it unless its absence would lead to confusion. Whether to use the Oxford comma can depend on the style guide you are following (an internal style guide for your company or otherwise), but many of my clients favor it for its role in clearly separating list items.

Do You Put the Comma or Period Inside or Outside Parenthesis?

I get asked this question a lot. Here’s how it works:

  • When the sentence inside the parenthesis is not a complete sentence, the comma goes outside the parenthesis.
  • If the information inside the parenthesis is a complete sentence, you will use punctuation just like a regular sentence with a comma or period inside the parenthesis. 

Semicolons (;)

Semicolons and colons have their place in the world. But what are the grammar and punctuation rules for writing and using these punctuation marks? Let’s explore.

Joining Two Related Sentences

Use a semicolon to connect two related sentences that could stand alone but are closely related. Example: “It was raining; we stayed indoors for our photoshoot.”

With Conjunctive Adverbs

When using words like ‘however’, ‘therefore’, or ‘moreover’ to join two sentences, use a semicolon before and a comma after the conjunctive adverb. Example: “I was feeling tired; however, I decided to keep working on my Canva project.”

Colons (:)

Colons give a hard pause in a sentence and get the reader ready for more incoming information. Here are the ways to use colons for your marketing copy:

Introducing a List

Use a colon to introduce a list of items. Example: “You need to plan for the following: time, budget, and assignments.”

Before an Explanation

Use a colon to introduce an explanation or a result. Example: “I know why the Facebook ad failed: there was no call-to-action.”

Before a Quote

Use a colon to introduce a quote that is formally announced. Example: “The CEO said: ‘Let’s increase the marketing budget.'”

In Time

Use a colon to separate hours from minutes when writing time. Example: “The train leaves at 3:45 PM.”

Em Dash (—)

I am personally a big fan of the em dash. Here are a few ways that you can use it in your marketing copy:

To Add Extra Information

Use an em dash to add a piece of extra information that is important but could be left out, enriching the message without cluttering it. Example: “Our latest campaign—launched just last week—has already surpassed expectations.”

Instead of Parentheses

Em dashes can replace parentheses to emphasize additional information more dynamically. Example: “The new product line—we’re launching it in Q3—targets millennials specifically.”

Before an Explanation or Conclusion

Use an em dash to introduce an explanation or a conclusion that follows a statement, adding clarity or impact. Example: “Our revenue grew by 15% this quarter—the result of a revamped marketing strategy.”

To Show Interruptions in Dialogue

In marketing materials or presentations, use em dashes to indicate interruptions or abrupt shifts in thought, which can make the content feel more lively and natural. Example: “If we increase our budget for digital ads—we need to discuss this today—we could capture a larger market share before the holiday season.”

En Dash (–) 

Not to be confused with the em dash is the en dash. There are a few places where you can use the en dash in marketing materials and much more, including the following:

Range of Numbers

Use an en dash to indicate a range of numbers, which is common in marketing for prices, dates, or statistics. For example, “Join our webinar series running from April 10–15 to learn advanced digital marketing techniques.”

Between Words Indicating a Connection or Conflict

An en dash is useful for linking words that describe a connection or a relationship, often used in marketing to highlight collaborations or dual offerings. For example, “Our latest initiative, the East Coast–West Coast marketing challenge, aims to inspire creative approaches to marketing.”

active vs passive voice

Active vs. Passive Voice

Are you writing in active or passive voice? This one is easy to overlook, but staying mindful of active vs. passive writing can make a difference in your brand’s presentation.

Active Voice

In the active voice, the subject of the sentence performs the action expressed by the verb. This voice is direct, clear, and concise, making it easier for readers to follow the narrative or instruction. It typically makes sentences more dynamic and assertive.


  • Active: “The marketing team developed a new campaign.”

Using active voice here puts the focus on the subject (“the marketing team”) and their action (“developed”), creating a strong, clear sentence.

Passive Voice

In the passive voice, the subject of the sentence is acted upon by the verb. However, it often makes sentences longer and more complicated.


  • Passive: “A new campaign was developed by the marketing team.”

This passive construction shifts the focus onto the action (“was developed”) and makes the doer of the action (“the marketing team”) less prominent, which might be useful in contexts where the action is more important than who executed it.

When to Use Active vs. Passive Voice

  • Active Voice: Most effective for most business and creative writing because it is more straightforward and vigorous. It is particularly useful in instructions, promotions, and general communications where clarity and engagement are priorities.
  • Passive Voice: Useful in scientific or technical writing where the focus is on the process or result rather than on the personal agent. 

Writing in Past vs. Present Tense

This is perhaps my biggest pet peeve that goes beyond grammar and punctuation rules for writing. Writing in the present tense can make a big difference in terms of the tone and even the confidence of your content. 

Each tense can set a different tone and atmosphere, influencing the immediacy and relevance of the narrative.

Past Tense

Writing in the past tense narrates events that have already occurred. It’s the most common tense used in narrative and expository writing because it allows you to craft a story with a clear sequence of events.


  • Past Tense: “Last year, the company launched a new product that revolutionized the market.”

Using the past tense here provides a historical perspective, suggesting a completed action and its impact over time.

Present Tense

Present tense describes events as they are occurring or general truths. It’s used in writing to create a sense of immediacy and engagement, making the reader feel as if they are experiencing the events in real-time. It’s also common in journalistic contexts and live reporting.


  • Present Tense: “The company launches a new product that revolutionizes the market.”

This use of the present tense makes the statement feel current and ongoing, which can be very effective in marketing materials or news articles to convey urgency and relevance.

When to Use Past or Present Tense

  • Past Tense: Ideal for telling stories, reporting past events, or discussing historical data. It helps to build a narrative arc and is useful in academic writing, biographies, and most literature.
  • Present Tense: Best for engaging readers with current issues, in instructional content, and when discussing literature and art (to give the sense that the work still lives). It’s also preferred in sports commentary and live reporting.

Dangling Modifiers

grammar and punctuation rules for writing

Those dang dangling modifiers can easily trip you up. A dangling modifier can lead to misunderstandings or unintended context in content, which might distract from your intended message. 

A lot of times, adding a pronoun to the dangling modifier will fix the problem. Otherwise, you will need to clarify the subject if it is not a person.

Here are examples of dangling modifiers along with corrections:

Examples of Dangling Modifiers

  1. Incorrect: After updating the website, the conversion rates seemed low.
    • Corrected: After we updated the website, the conversion rates seemed low.

The incorrect sentence implies that the conversion rates updated the website, which is illogical. The corrected sentence makes it clear that ‘we’ updated the website, and subsequently, the conversion rates seemed low.

  1. Incorrect: Designed to increase engagement, customers didn’t respond well to the new campaign.
    • Corrected: Although it was designed to increase engagement, the new campaign did not receive a positive response from customers.

Here, it sounds as if the customers were designed to increase engagement. The corrected version clarifies that it was the campaign that was designed to increase engagement, which did not resonate well with customers.

  1. Incorrect: Using advanced analytics tools, the marketing strategy was poorly executed.
    • Corrected: Even though we used advanced analytics tools, the marketing strategy was poorly executed.

The original makes it appear as if the analytics tools were responsible for executing the strategy. The correction clearly assigns the execution of the strategy to the team, despite the use of advanced tools.

Get Help with Grammar and Punctuation Rules for Writing

Are you struggling to make your web copy error-free and enjoyable to read? I can help! Equipped with a degree in Professional Writing & Editing, I can assist with editing web copy, blogs, and many other types of marketing content. Get in touch with me to learn more about editing and proofreading services today!