1- Use of Second Form of Verb:
Many people use second form of verb with the word “did”, it is common mistake but ponder over the concept that “did” is already second form of helping verb, so with it, we have to use first form of verb.
Example:
Did you received the book? ———–? Incorrect
Did you receive the book ——–? Correct

2- Use of “Its and It is”:
“Its” is used for possession whereas “It is” is shortened as “It’s” while speaking fluently but notice that generally Apostrophe Sign is used for possession but here it’s quite opposite. Its use is not for possession over here.
Example:
It is my laptop.
Its price is 40 thousand rupees.

3- Use of “The”:
As described in definition of Articles, “The” is used with Common Noun to make it specific i.e. when we are going to refer something or you can say that when something has been narrated before and we want to mention it e.g.
Example:
It is a book. The book is on the table.

4- Use of “Since/For”:
These are the words used for timing. “Since” is used for some fixed time and “For” is used for some time, we are not sure about. But with both these timing prepositions, “Been” or 3rd form of verb is must.
Example:
He has been living in Lahore since 1996.
I have written his article for the past four hours.

5- Use of “Then & Than”:
“Then” is adverb that we use to emphasize while “Than” is used for comparison between two nouns. It is most common mistake and many senior persons don’t know it.
Example:
They had a lunch and then they started traveling.
She is more genius than Sana.

6- Use of “I’:
This is an important thing to keep in mind that when we use “I” as Pronoun, it is always written as capital whether it comes in the start, centre or end of the sentence whereas we use words starting with alphabet “i”, capital in the start or for Proper Noun only.
Example:
I have decided to depart for Lahore. Should I?
We use internet for getting information.

7- Use of “May” & “Can”:
Both have same meaning but there is difference in their use. The word “May” is used in the sense that we are going to get permission or it is used in the start of a sentence to wish some prayer but “Can” is used to show possibility of something to happen or to be able to do something.
Example:
May I come in?
May you live long!
He can drive the car.

8- Use of “Until”:
The word “Until” is a conjunction and is used in a conditional sentence but remember that though it is used with positive and negative sentences but after it, there is no negation added in the sentence rather it may be before this word in a sentence.
Example:
She will not be discharged from the hospital until she recovers.
He passed his childhood in Dubai until 2010.

Other mistakes are with Pair of Words which we call Confusing Words and must be noticed how to distinguish them.