As I gain more experience as a writer, I am highly convinced, writing is not a child’s play. It is not just about telling a story or rephrasing someone else’s work, it is about the skill of crafting a perfect piece. The first thing in good essay writing is learning the basic grammar rules and making smart choices about the use of words. In addition to this, a smooth flow of ideas that does not confuse the reader is equally important.
Use of Active Voice
Whenever possible, write my essay in the active voice. An active voice is subject to performing an action. While passive voice is, the action is received by the subject.

Common Mistake committed by students
To create a meritorious essay, take care of the following areas, for these are the areas where students commit most of the mistakes.
Use of Commas:
The Comma is a tricky punctuation mark and its use depends on the writer's judgment. Always have the right balance of commas, neither use too few nor too many. Commas add meaning to the statement and help a reader understand better.
Take care of Adjectives vs. adverbs
This can be understood from the following example:
People don’t run quick but run quickly. Quickly is an adverb while quick is an adjective. Adjectives should be used to modify nouns, whereas adverbs are used to modify verbs.
Verb Tense
Beyond past, present, and future, multiple tenses exist. Show special care when you mix up tenses. Such as mixing up simple past and past perfect tense.
If you hire a professional essay writer from a legit essay writing service, you will notice they are very keen on these grammatical issues.
Subject-verb agreement
Is English a second language for you? This can be tricky for you to understand due to verb conjugation. The subject of tense must match with the verb.
Order of Words
Listen, the order of words can make or break a sentence. Starting a sentence with an incomplete clause or phrase will end up in the creation of a grammatically wrong sentence. Never start the sentence with something like, while crossing the street.
Same Sentence Types Throughout the Essay
You are not a good writer if your reader feels bored in between your essays or papers. To avoid this, use different types of tenses. Follow these tips to attain this:
Absence of Cumulative sentences: Start your sentence with the main idea and add modifiers to explain the sentence to the reader.
Example: The storm caused severe damage, knocked down trees, broke power lines, blew roofs off buildings.
Missing Periodic sentences: To change from the above sentence type, add modifiers first and then come to the main idea.
Example: Knocking down many trees, breaking power lines, and Blowing roofs off buildings, the storm caused severe damage.
Occasional Questions: This is very effective to grab the reader's attention.
Sentences of Varying Length: Make short, and long sentences while staying in the limit of the standard length of sentences in academic writing.
Right Conjunction: Use the right conjunction to enhance the clarity of your sentence.
Clichés
There are multiple reasons you must stay away from clichés. If you read through a professional essay, you will never find any cliché in that essay. This is because they know:

Being unoriginal must be the mortal enemy of any writer. Clichés make you sound unoriginal
Clichés damage your image as a writer; you are assumed as lazy.
It often results in poor grades from teachers.

The list shared above is just a taste of concrete grammar rules. These points are mostly overlooked by students. Even if you avoid these, you are close to a perfect essay. no one can stop you from being an expert essay writer if your grammar is good enough! You can also get a professional essay writer free of cost to proofread them to ensure such errors are rectified. 
Remember! Consistency is key. Plus, always keep a style guide to help you while you are writing.

Destructive sins of essay writing One MUST Avoid | 2021 Guide