This means:
* Identifying the source's perspective: What are the author's beliefs, values, and experiences? How might these influence their account?
* Considering the source's context: When was the source created? Where was it created? Who was the intended audience? How might these factors shape the information presented?
* Looking for evidence: Does the source provide supporting evidence for its claims? Are there alternative interpretations or explanations?
* Comparing and contrasting: How does this source compare to other sources on the same topic? Are there any contradictions or inconsistencies?
By approaching sources critically, historians can begin to understand the biases that might be present and develop a more nuanced and accurate understanding of the past.