As an editor, I see the same simple punctuation mistakes time and again costing students valuable marks when the overall quality of their work deserves a much higher grade. Whether it is everyday essay writing or an undergraduate dissertation, correct grammar punctuation is the quickest way to see a huge improvement in the quality of your work (not to mention better grades!)
The good news is that help is at hand! Listed below are examples and explanations of the most common errors in using punctuation marks, along with some simple tricks to help you remember how to correct them.

Using commas correctly when writing essays

Whilst they can be very handy for breaking up long sentences, there are certain places in your writing where commas don’t belong. The biggest mistake of this kind is putting a comma before the word ‘and’. As the word acts as a natural bridge between two parts of a clause or sentence, there is almost never a need for a comma before it. This is one of those tricky grey areas of grammar where some authorities believe a comma is outright wrong, others that it is allowable. So my best advice would be to stay on the safe side by avoiding it where possible.

For example, a comma is necessary here:

“Mary Shelley and Bram Stoker are writers of the Gothic genre, both of whom were revolutionary for their time”

But NOT here because of the ‘and’:

“Mary Shelley and Bram Stoker are both writers of the Gothic genre and were revolutionary for their time”

TOP TIP: Try not to use a comma before ‘and’

One place where a comma is usually needed, however, is before the word ‘which’. This is one of the most common places as an editor where I see people missing out necessary punctuation marks. The word ‘which’ is often used where a pause is needed in the sentence (usually because the next part deals with a different idea or thought), whilst ‘that’ should be used when the sense of the sentence carries straight on. As the word ‘which’ indicates a new thought or idea, a natural pause is necessary, so a comma should be inserted, but many students seem to feel the word itself performs this function and omit the punctuation mark.
For example, a comma is necessary here:

“Electrons, protons and neutrons make up the atom, which is the smallest part of an element”

But NOT here:

“Electrons, protons and neutrons are the three types of particle that make up an atom”

Of course there are some exceptions to this rule, when the word ‘which’ is being used in a different sense.

For example:

“He opened the box in which she had packed the lunch”

It is also possible to use the word ‘which’ without a comma in a restrictive sentence when it is referring to a specific object.

For example:

“The cake which had been cut was on the table”

However many more fussy markers and authorities would argue that the word ‘that’ would be better substituted here, so it is best to avoid it just in case.

TOP TIP: If when you read the sentence through there is a natural pause before the word ‘which’, or it introduces a new part of the sentence, don’t forget to precede it with a comma.

Correct use of quotation marks and apostrophes

Many students lose crucial marks by confusing when to use the single apostrophe (‘) with when to use double quotation marks (“). To use English grammar correctly it is essential to master the use of quotation marks. The rule here is simple – the double quotation mark is used for any dialogue or speech, and whenever quoting from a text.

For example:

“Come along,” said Mum, “we’re going to be late.”


The most famous line from Hamlet, “To be or not to be, that is the question”, epitomises the indecisiveness of the hero.

Single quotation marks are only used when describing a questionable or false assumption held by some to be true but widely doubted or disproved.

For example:

The ‘ghost’ the children had seen proved to be merely a sheet blowing on the washing line.

TOP TIP: Always use double quotation marks (“) for dialogue and quotes

Punctuation marks after speech marks

Another very common punctuation mistake that can be easily avoided is forgetting the punctuation at the end of a person’s speech. Just remember, even if it feels as if the sentence flows straight on, even if the person is going to speak again in the same sentence, correct grammar use dictates that you must use a punctuation mark every time you close speech marks.

For example:

“Thomas!” shouted Mum, “hurry up and get dressed.” “Yes Mum,” called Thomas, “I’m on my way.”

TOP TIP: Never close a speech mark without using punctuation.

Remember, punctuation and grammar are essential to excellent essay writing. Use these simple rules and top tips to rid your writing of those common punctuation mark slips and get the higher marks you deserve, every time. Remember, many of these mistakes are easy to make but you can still correct them by leaving yourself an extra few minutes at the end of your essay to check it through, paying special attention to your punctuation marks and remembering our punctuation rules for the correct apostrophe, quotation mark and comma use.