Methodology includes...

Here are examples.

Research design: "I will compare Britain, France, and the United States between 1750 and 1870."

Source selection: Parliamentary debates, legal codes, factory reports, newspapers, letters.

Methods of analysis: Comparative historical analysis, discourse analysis, institutional analysis.

Criteria for evaluating evidence: Is the source authentic? Is it contemporary? Is it biased? Is it corroborated by other sources?

Rules of inference: What conclusions can legitimately be drawn from the evidence? Which conclusions go beyond the evidence?

Methodology tells you...

What evidence to collect: For example, if you are studying the motivations behind abolition, speeches, letters, and legislative debates are more relevant than factory production statistics alone.

How to evaluate it: A private letter written at the time may carry different evidentiary weight from a memoir written forty years later.

How to use it: If several independent sources point in the same direction, you may argue that they collectively support your interpretation. If the evidence is mixed, your conclusion should reflect that uncertainty.