When searching a database, look for the option to limit your results to peer-reviewed, academic, or scholarly articles only.
As you find articles, use the questions in your assignment as a checklist to determine if the article meets the criteria for the assignment
When choosing keywords, look for synonyms. For example searching for "battles" and "conflicts" will often result in more results than "battles".
Many scholarly journals are considered Peer Reviewed. Prior to publishing an articled in a peer-reviewed journal, the article is sent to a group of editors or scholars in the field and is reviewed. The reviewers evaluate the methodology, research design etc of the article prior to approving it for publication.
Many databases including JSTOR or Project Muse provide the ability to ask that the results of a search come from peer-reviewed or refereed journals. Usually there is a check box on the search screen page which will guarantee that results come from peer-reviewed articles.
Not all databases allow limiting to peer-reviewed articles. There is no way to include "peer reviewed" in your search strategy.
In order to determine if an article that you retrieve from a database comes from a peer-reviewed journal, you can use the database Ulrich's Periodicals Directory. It is listed under Databases on the Library Website. In order to find the database from the Libraries Website, go to Databases by Title and click the letter "U". There is also a link at the bottom of this section.
Use the Quick Search in Ulrich's and put in either title keywords for the journal or the exact title. An exact title, for example. would be Speculum.
Click search. If the results display the title with a black and white striped referee's jersey to the left of the title, the journal is refereed or peer reviewed.