Use quotes to lock down specific phrases: “microbial mats” “magnetic anomalies”
Limit your keywords to specific database fields for greater focus. This forces your search term to be in a specific place (like the article title). Helpful if you get far too many results.
Use a truncation symbol to capture all word variants, eg sediment* for sediments, sedimentary, sedimentation, etc.
Use the OR connector to group related keywords or concepts: (RSL or “recurring slope lineae”); (microb* or microorganism*). Use parentheses if necessary.
Use filters and facets – good options are by subject term, or by type of document (like scholarly journal article or dissertation or book chapter)
Limit to a date range that makes sense for your topic
Look at how your results are sorted. It’s usually by relevance, but not always. If they’re sorted by date instead, try changing the sort order. Sorting by the number of times cited can be useful.