It is very difficult to summarize the art of mastering english grammar in an article. However, In my opinion there are some errors which are committed very frequently even by the most knowledgeable writers and authors.Before you submit your assignment, article , news item , story etc you may want to check for the following errors which clean up your article to a great extent-

1. To join two independent clauses, use a comma followed by a conjunction, a semicolon alone, or a semicolon followed by a sentence modifier.

2. Use commas to bracket nonrestrictive phrases, which are not essential to the sentence's meaning.

3. Do not use commas to bracket phrases that are essential to a sentence's meaning.

4. When beginning a sentence with an introductory phrase or an introductory (dependent) clause, include a comma.

5. To indicate possession, end a singular noun with an apostrophe followed by an "s". Otherwise, the noun's form seems plural.

6. Use proper punctuation to integrate a quotation into a sentence. If the introductory material is an independent clause, add the quotation after a colon. If the introductory material ends in "thinks," "saying," or some other verb indicating expression, use a comma.

7. Make the subject and verb agree with each other, not with a word that comes between them. 8. Be sure that a pronoun, a participial phrase, or an appositive refers clearly to the proper subject.

9. Use parallel construction to make a strong point and create a smooth flow.

10. Use the active voice unless you specifically need to use the passive.

11. Omit unnecessary words.