Review your essay for any problems with the citation of the sources you have consulted in preparing the essay. Review your quotations and paraphrases to be sure they are appropriately introduced and punctuated. Bibliography software such as Zotero can be very helpful in the process, but a close check is still necessary as the software does sometimes make errors. In particular:
Have you checked all in-text citations to ensure they are formatted and documented accurately and appropriately according to the system you are using (MLA, APA, etc.)?
Have you checked your bibliography or reference list to ensure that the sources are in alphabetical order and formatted accurately and appropriately according to the system you are using (MLA, APA, etc.)?
Pay particular attention to:
Punctuation: location of periods, commas, colons
Titles: italics, quotation marks, capitalization
Capitalization of proper nouns, i.e., names of places and people
Noting page numbers, i.e., p. or pp. or numbers alone
The Creating Bibliographies module can help you understand the procedures and requirements for appropriately citing sources.