It is better to be overly formal in college writing than to be too casual. Generally speaking, in U.S. colleges, standard American English is the rule. Unless you are told otherwise, it is best to assume that formal standards apply – even for journal writing. Avoid the tendency to write for your instructor as if you were speaking to a peer – even if you find your instructor to be very approachable.
Person: I, You, One, He, She, They
No hard and fast rules apply when it comes to using first, second, or third person in your papers. Third person is generally preferred because it is more formal. However, a stiff adherence to the use of third person can, in some instances, become cumbersome and/or seem inappropriate. For example, if you are asked to write about your opinion, referring to yourself in third person (“The writer thinks that. . .” or “One is of the opinion that . . .”) may be unnecessarily distracting and even confusing. In this case, it may be preferable to refer to yourself in first person (i.e., as “I”).
The use of second person (addressing your reader as "you") is more often than not inappropriate in college writing. Ask yourself whether the “you” specifically refers to the instructor. If not, then “one” or a similar third-person reference is probably a better choice. An exception to this would be a creative writing assignment, such as a poem, in which a more intimate tone is desirable.
Click on the links below for more writing tips:
Sentence Structure & Punctuation
Punctuation Pointers: Colons & Semicolons
Punctuation Pointers: Apostrophes & Quotation Marks
Grammarly.com (Where you can paste your writing for computerized feedback)
Grammarly Handbook (A free online grammar reference)
Grammarly Answers (Where you can post questions and get answers)