Chicago (or the closely related Turabian) style is the most frequently used style for the discipline of history. It allows you to use either footnote or parenthetical author-year citation -- ask your professor which (s)he prefers. In September 2017, the 17th edition of this style guide will be published. At that time, Ellis Library will acquire a copy and shelve it on the Ready Reference shelves behind the Information Desk for general use. The Journalism and Health Sciences libraries have copies of the 16th edition.
There is a brief online guide to citation using the Chicago style at the University of Wisconsin Writing Center. The University of Georgia has produced a brief online guide to the Turabian style.
Feeling lost and alone when writing your paper? Steve Kreis, who got his Ph.D. in history at MU, has designed The History Guide, with good, practical ideas on finding and narrowing topics, putting together what you find in your research, and writing a good paper. (A side note: anyone considering graduate school in history should read Dr. Kreis' autobiography.)
Finally, here are a few ways to write an interesting paper:
1) Trace a change in a state of affairs and make a stab at explaining the change.
2) Relate an unofficial version of an "official story."
3) Contrast real life with a common stereotype or popular image. (Cowboys in film vs. cowboys in historical court documents)
4) Compare a real-life situation or event with a theory of social life or change. How much (or little!) does this theory account for what happened?
5) Distill a pattern of thought or action shared by people in a time period out of the historical record. (Marriage was treated in X manner in B set of documents, but in Z contradictory manner in C set of documents)
6) Make up a typology, or finite set of categories, that makes complex data easier to comprehend. (wilderness tourists, sports fishing tourists, historical tourists, family/leisure tourists as categories of visitors to a national park during a given time period)
7) Compare and contrast two groups of people or two events that seem at first glance to be either very similar to each other or completely unrelated/different. Show what makes them similar and different.(ex.: Reformed and Catholic sacraments in 16th-Century German life)
In general, emphasize the unexpected: something appearing monolithic at first glance is really complex; something that seems to have "always been that way" actually evolved; a religion or government appearing to function from the top down actually experienced change from the bottom up; something appearing to be an effect is really a cause; something that appears as a cause is merely a correlation.