Sources in history writing can be primary or secondary. Primary source documents are from a given time period and are used to make a case for a certain analysis or interpretation of an aspect of that time period. A primary source essay is not objective; it is narrative and arranged chronologically. Secondary sources discuss a historical time period after it has passed. They are usually a review of several documents, a synthesis the writer compiles to find common, supporting or contrasting elements to make a point or delve deeper. Secondary source papers agree or disagree with someone else's interpretation of historical events and are usually not chronological. A solid history essay will use both primary and secondary sources as references.
Karen Gocsik of the Dartmouth Writing Program summarizes that one difficulty in writing history papers is "the process of transforming facts into evidence and evidence into argument." Gocsik points out that, because "facts do not exist in a vacuum," the writer must be mindful that how a fact is presented or stated determines how the essay will be both shaped and received. Determine the validity of sources and cross-check them. Evaluate the context of each source, such as the number of witness accounts used and when, where and by whom the source was compiled. An important part of getting good at writing history essays is source evaluation. This also helps an essayist determine the inherent bias in a piece of writing. Gocsik cautions, "Often, the history of a source's biases is as significant to interpret as the narrative itself."
Research footnotes and the bibliography of all sources used in writing your paper. This will tell you if a variety of opinions, evidence and accounts were used, which speaks to the source's credibility. Note if the source author is only referencing one source or one type of source in their papers.
Consider the cultural factors present in the time period discussed in your history essay. Not only does this prevent turning off potential supporters of your argument, it also will foster an environment where you can carefully consider all of the elements of your case. As Gocsik puts it, "You cannot evaluate Victorian society`s approach to 'fallen women' using modern legal definitions of rape. Understand that 'common knowledge' and 'common values' in any given time period are influenced by numerous factors and are never absolute."
Forgo including related information, however fascinating, if it is does not tie in to your main points or add to a necessary understanding of the historical subject. This is called "reasoning historically." Include information that contradicts your argument to concede or disprove it.