What question was asked?
Find the research question in the original source. A short headline may remove the setting, the comparison or the timeframe that gave the result its meaning. Write a one-sentence note that keeps those details visible.
What was studied?
Identify the experimental model or participant group. Keep findings in that setting rather than treating every study as an answer about a person or a product.
What was compared?
Look for the comparison and the endpoint. Separate what was measured from what the authors discuss as a possible explanation.
What uncertainty remains?
Read the authors' limitations and the full results section. Note questions the study cannot answer, including differences in model, measurement or follow-up.
Can someone retrace the source?
Save the citation and a persistent link. A useful reading note lets the next reader check the same passage, table or method.