1. words and phrases (subject headings)
Don't stop with first words that come to mind. AND OR " "
2. Use several databases. Take advantage of different coverage and ranking algorithms.
3. Other, but especially cited (in introductory paragraphs mostly) and Cited by (in Google Scholar and elsewhere too). Cited by __.
Getting full text -- Use Google Scholar, but also try Libkey.io . Add a DOI number to Libkey.io/ . You can also ask me (wiswellj@) or try out our Interlibrary system (if you have a day or two).
Organizing it all -- Strongly consider using Zotero. Zotero.org
More questions or problems? wiswellj@