When we write history we are using evidence to make an argument about the past. We often agree on the sequence of events, but scholars must interpret historical evidence in order to understand why things happened, what were the main causes or motivations for action, and how did aspects of a society change over time? When we write about history, we are trying to persuade our readers that our interpretations are the best using evidence and sound arguments.
The main components of historical writing are primary sources and secondary sources.
Primary sources are the building blocks of historical research - they are the documents or artifacts closest to the topic of investigation that you will use as evidence to support your interpretation of the past. Often they are created during the time period which is being studied (e.g. correspondence, diaries, newspapers, government documents, art), but they can also be produced later by eyewitnesses or participants (memoirs, oral histories).
You may find primary sources in their original format--often in an archive--or reproduced in a variety of ways: published in books, on microfilm, or digitized in a searchable database.
For comparison, secondary sources are narratives, interpretations, and critical analyses of the past, written by historians or others and (hopefully) based on primary sources. They are created by writers who have the necessary distance in time to put past events and people into their broader historical context. Secondary sources build upon and interpret primary sources, and typically respond to and debate with the secondary sources created by others. Secondary sources also come in a variety of formats, including scholarly books (also called monographs), peer-reviewed journal articles, presentations at professional conferences, professional blog posts, or magazine articles.
When we write about history, we learn from historians who have already written on our subject. We also respond to their interpretations and offer some of our own original ideas. We may even disagree with other historians' interpretations of the past.
Writing about what other historians have said about a topic is called historiography. Historiography can be described as the "history of the history" on a given topic. In other fields of study, this might be called a literature review. Becoming familiar with the historiography on a topic helps us to understand existing arguments, refine our own interests and research questions, and engage with the community of historians working on similar topics.
Historiography is an important part of all writing about the past. In it, we explain to our readers:
The "what" of history might include the events that historians write about, why they are important, choices historians make about when their story begins and when it ends (which historians call periodization), and what is meaningful about these narrative choices.
The "how" of history includes which primary source materials are used as evidence, which methods are used for interpreting that evidence, and which if any theories or "schools of thought" have influenced this interpretation of the past.
Determining the need for more work in an area is largely up to you! Have some primary sources been left out of historians' works? Do you have a new way to interpret or recombine well-known primary sources? Are there approaches from other disciplines that can be used to create a new perspective? What new and meaningful story will you explore and share? This is your research question!