When quoting, indicate in the text whom it is that you are quoting, give some indication when introducing the quotation of why you are introducing it, and use your own words after the quotation to indicate what you want to reader to make of it. Avoid having too many large, block quotations. Remember, this paper is supposed to present your thinking, not to demonstrate your ability to mine the thinking of others. The passive voice should never be used. Don't use contractions in formal writing.
Verbs has to agree with their subjects.
Watch out for colloquial verbs which have cropped up or snuck into our language. About sentence fragments. No incomplete sentences. Avoid run-on sentences they are hard to read. Avoid commas, that are not necessary.