Exclamation points are usually placed at the end of sentences that are meant to convey strong emotion. They should be used sparingly, especially in academic writing, because they become meaningless with overuse, and can be distracting to readers. The emotional impact of writing is best conveyed by words, not punctuation.
Consider the following passage, and whether the exclamation points help to communicate the writer's message.
The first time Kevin saw Dragon, he immediately understood the difference between a well-trained guard dog and a "mean-because-he's-been-neglected" guard dog! Dragon wasn't just a junkyard mutt; he was a German Shepherd, and looked like the dogs that accompany the police when they search for drugs. But Dragon wasn't trained to look for drugs; he was trained to look for drug addicts, and to keep them out of Floyd's yard! The fence around the yard was nine feet tall and topped with razor wire. And now the gate, the only thing that separated Dragon from the rest of the world, hung open, swinging in the morning breeze!
The exclamation points used in this passage don't help to convey meaning. The words used (and the subject) would communicate the same message, including the emotional content and tone, without them.
Perhaps the exclamation point that ends the paragraph could be left in place, but a period would work just as well. The tone of that sentence - established by the image of the swinging gate and Dragon's absence - would be more ominous without the exclamation point.
Here's the same passage without exclamation points. You can see that it's an improvement of the original.
The first time Kevin saw Dragon, he immediately understood the difference between a well-trained guard dog and a "mean-because-he's-been-neglected" guard dog. Dragon wasn't just a junkyard mutt; he was a German Shepherd, and looked like the dogs that accompany the police when they search for drugs. But Dragon wasn't trained to look for drugs; he was trained to look for drug addicts, and to keep them out of Floyd's yard. The fence around the yard was nine feet tall and topped with razor wire. And now the gate, the only thing that separated Dragon from the rest of the world, hung open, swinging in the morning breeze.
Semicolons confuse some writers, especially those who are new to academic writing. However, they're actually easy to understand and use. It can be helpful to think of a semicolon as combining some of the characteristics of a period and a comma.
Writers most often use semicolons in two ways. The first of these is to connect two independent clauses to form one sentence. This indicates that there is a stronger relationship between the clauses involved than between two consecutive sentences separated by a period.
EXAMPLEI wanted to go to the party; you know I'm always looking for a good time.
EXAMPLEWalt had never felt comfortable in the car; he always had the feeling that it didn't belong to him.
In both of these examples, the writer uses the semicolon to indicate to readers that there is a close relationship between the two clauses. This sense of strong relatedness would be lost if periods had been used to separate the clauses, making each of them two sentences instead of one.
The second reason that writers use semicolons is to separate complex items in a list where each item consists of several words, or contains commas.
EXAMPLEThere are two ways to write: with a pen or pencil, which is cheaper but slower; or with a computer and printer, which is more expensive but faster.
If the writer had used additional commas instead of semicolons in this sentence, it would be harder for readers to understand where one list item ends and the next begins.
In most listing situations, however, it's better not to use semicolons. Items in a list should be separated by commas whenever doing so will not confuse readers.
EXAMPLEMy favorite sports are soccer, football, and rugby.
Semicolons are useful tools, but they must be used carefully.
Colons are similar to semicolons, but as the name suggests, their action is more complete and forceful (i.e., it's not semi). Like the punctuation marks discussed in the preceding sections, colons are sometimes overused, which can result in decreased effectiveness (and increased distraction) from readers' perspectives.
They are impactful, however, in a number of situations, including the following:
EXAMPLEI gave you three jobs today: washing the car, cleaning your room, and folding your clothes.
EXAMPLEThe following students have achieved perfect attendance: Janice, Mark, and Roland.
Academic books and articles often use colons to separate a title and subtitle.
EXAMPLEAncient Greece: From Prehistoric to Hellenistic Times
Colons can also link two ideas closely. In the second sentence below, the colon actually ensures readers understand that the bar with the endless happy hour is the narrator's dream come true, not something else in the narrative.
EXAMPLEHe knew there was only one option left to him: to fight.
EXAMPLEIt was a dream come true: a bar with an endless happy hour.
Sometimes the use of a colon indicates a stronger relationship between the ideas in the two clauses than the use of a semicolon would.
EXAMPLEThe senators remained entrenched: neither was willing to compromise.
The connection in these examples is meant to be a strong one, and the use of a colon is a good way to make that clear.
Quotation marks are used to indicate a verbatim account from a source, and to identify speech in narrative writing. They can also be used to draw attention to specific words and ideas.
In this last respect, they can indicate sarcasm or disbelief— similar to the way in which people use "air quotes" when speaking.
EXAMPLEI'm sure her new boyfriend is a "winner," just like the last one.
The quotation marks indicate that the word "winner" is being used ironically in this example. It's important to be careful when using quotation marks in this way. It's easy for readers to confuse them with quotation marks that signal a real quotation or dialogue, depending on the genre. This is usually not the best way to convey irony or sarcasm, especially in an academic context.
Writers can also use quotation marks to draw attention to terms that they are defining or discussing directly.
EXAMPLEThough people still use it to sound intelligent, "irregardless" is not a word.
In this sentence, the quotation marks highlight and emphasize "irregardless" for readers, clearly identifying it as the topic of the sentence.
As with many other forms of punctuation, quotation marks are an effective tool for directing readers' attention, but overusing them can have the opposite effect.