Define the boundary
Write down the question your review serves, the relevant period and the kinds of evidence you will consider. Keep a record of your search terms and selection decisions. The method should fit the assignment: an ordinary narrative review and a formal systematic review have different requirements. Do not claim systematic coverage unless you have actually followed and reported an appropriate process.
Organise by ideas
Build a table with each source’s question, method, conclusion and limitation. Then group sources by the issue they address rather than simply summarising one author after another. Look for disagreements that follow from different definitions, populations or methods. A disagreement becomes informative when you can explain its basis instead of counting how many authors support each side.
Make the gap specific
“More research is needed” is usually too vague. Specify which relationship, context or measurement remains uncertain and why your proposed work could help. A gap is not automatically a valuable project; feasibility and importance still matter. End by showing how the literature changes your question, assumptions or method. The review should shape the research, not merely decorate its introduction.
