Revisit the PRISMA workflow and checklist to ensure that you are documenting your search strategies properly. One of the hallmarks of a systematic review lies in the reproducibility and published documentation of your search strategies. Once published, a reader should be able to cut and paste your search strategy to replicate your findings. This ensures the integrity of any systematic review.
Further search guidelines are available from the following organizations:
Revisit your preliminary search strategies from your "Probing Literature Review." Develop these more carefully by using a combination of authoritative language (like Medical Subject Headings - MeSH, CINAHL Headings, etc.) and natural language (keywords). Apply your inclusion and exclusion criteria to help refine your search further. Collect new terminology as you search and read. The way you articulate your search strategy will evolve with every search and, as a result, you may need to revisit databases multiple times. Document all terminology and searches along the way.
Librarians are especially helpful at developing search strategies that help narrow results and finding difficult to find content. If you are getting thousands of results, consult with a librarian right away. Your strategy needs refining! Why?