The following techniques can help the writers to avoid punctuation mistakes.

1. The comma is always used after introductory clauses, phrases or words.

Incorrect: However the people who don’t sleep well can suffer from different health problems.

Correct: However, the people who don’t sleep well, can suffer from different health problems.

However should be followed by a comma because it’s an introductory word.

Incorrect: To become a good player of cricket you must have to practice well.

Correct: To become a good player of cricket, you must have to practice well.

“To become a good player of cricket” should be followed by a comma, as it is an introductory infinitive phrase.

Incorrect: if someone wants to get good marks he must do some hard work.

Correct: if someone wants to get good marks, he must do some hard work.

“If someone wants to get good marks” must be followed by a comma because it’s an introductory clause.

2. The unnecessary information should be followed by a comma.

Incorrect: Jonathan Gilbert who is a biology student started to learn programming as well.

Correct: Jonathan Gilbert, who is a biology student, started to learn programming as well.

“Who is a biology student” should be followed by a comma, because it’s a clause and contains unnecessary information.

3. Commas are not required for necessary information.

Incorrect: The man, who murdered his father, is in police custody.

Correct: The man who murdered his father is in police custody

“Who murdered his father” does not need to be followed by a comma because it’s necessary information that which man is meant.

4. The coordinate conjunction that connects two main clauses must follow a comma.

Incorrect: The robber ran quickly but the tourist managed to reach the safety cabin.

Correct:   The robber ran quickly, but the tourist managed to reach the safety cabin.

The clauses that are connected by but could stand as a complete sentence: “The robber ran quickly” and “The tourist managed to reach the safety cabin.” A comma is not required, when a compound is connected by coordinate conjunction: “The tourist saw the robber and ran quickly towards the safety cabinet.”

5. A comma splice occurs for the joining of two independent clauses because a comma is not strong enough for this.

Incorrect: The financial crises lead him to do a job, however he was more interested in keeping up his studies.

Correct: The financial crises lead him to do a job, however, he was more interested in keeping up his studies.

Also Correct: The financial crises lead him to do a job. However, he was more interested in keeping up his studies.

When two independent clauses are connected by comma, a comma splice occurs. Here, the independent clauses are: “The financial crises lead him to do a job.” and “However, he was more interested in keeping up his studies.” In this case, “however” is a conjunctive adverb. It is providing an alteration between two feelings, but it is not a linking word like but or and. It is best to avoid a comma splice which can be done by adding a semicolon at the end of the first clause or by terminating the first clause with a full stop and starting a new sentence with a bold letter.

6. In ordinary narrations, the commas are not required before a noun clause. 

Incorrect: The adventurers get to know, that the caves are closed for the protection of bats.

Correct:   The adventurers get to know that the caves are closed for the protection of bats.

 

“The caves are closed for the protection of bats.” is a noun clause. The function of the clause is to act as a direct object of the verb in the independent clause, get to know.

7. Before a direct quotation, a comma is required.

Incorrect: The magician said “Don’t pay attention to the person behind you.”

Correct: The magician said, “Don’t pay attention to the person behind you.” 

8. After a complete sentence, colons can be used to present a list, word, clause, phrase or quotation.

Incorrect:    Rahim’s favourite ice-cream flavours are: vanilla, chocolate and strawberry.

Correct:    Rahim’s three favourite ice-cream flavours are: vanilla, chocolate and strawberry.

“Rahim’s favourite flowers are” is a fragment of a sentence and a colon should follow a complete sentence which is introducing a thought expanding on sentence meaning.

9. The independent clauses need a full stop that are not part of complex or compound sentences. The result is a “run-on-sentence” when a full stop or period is not present.

Incorrect: The batsman hit a huge six the people were roaring with emotions.

Correct: The batsman hit a huge six. The people were roaring with emotions.

The easiest way to correct the “run-on-sentence” is to end the first clause with full stop and start the other sentence with a block letter.

10. In mature writing, multiple exclamation marks should be avoided.

Incorrect: Before she got surprised, the boy fell into the water!!!!

Correct: Before she got surprised, the boy fell into the water! 

In formal writing, it is rare that an exclamation is required but one is sufficient.

Bonus: Simple emphasis does not require any quotation mark.

Incorrect: You are required to take at least one “defence” course every year.

Correct:  You are required to take at least one defence course every year.

 

According to some context, when a quotation mark is placed in a sentence, it shows that the word is used other than the obvious meaning. When quotation marks are used by writers for simple emphasis, it could annoy the reader. Everyone does not like to waste their time finding a separate meaning for a word that does not have really have it.