Define the scope of the review
Identify the concepts, source types and disciplinary boundaries relevant to the question. Record searches and selection decisions at a level appropriate to the type of review. Do not label a selective narrative review as systematic without the methods to support that description.
Make an evidence matrix
For each source, record its question, context, design, finding, limitation and relevance. Organize the rows by themes or disagreements rather than publication order alone. Use the matrix to identify where results are consistent, conflicting or difficult to compare.
Build paragraphs around claims
Begin with an analytical point, use sources as evidence and explain what their relationship means. Distinguish the original authors’ conclusions from your interpretation. Include important counterevidence and avoid citing a review as though you had read every primary study it mentions.
State a bounded gap
Explain whether the gap concerns a context, method, population, mechanism or unresolved disagreement. Show how your project addresses part of it within practical constraints. “No research exists” is a strong claim that requires more than a quick keyword search.