Keep in mind, or better yet, print out a list of the most common mistakes so that you can check yourself right away during the assignment:
Violation of logic. "Jumping" from one thought to another, illiterate selection of arguments, inconsistency in the content of the parts of the whole among themselves violate the logic of the narrative.
Verbosity. Try to use only the most necessary words. If something can be crossed out without affecting the understanding of the meaning, feel free to cross it out.