Use the brainstorming process to get some ideas for your search. Example if your topic is water pollution what other words might mean the same thing?
Also search for proper names in quotes so you only get the person you intended.
"John Bellamy Foster"
"Robert Bullard"
"Van Jones"
For multi word terms it might be quicker to search for the term in quotes such as "green new deal" so that you get the exact meaning you are intending.
It's always better to have as many search terms as possible. Combine the terms with AND to Narrow your search. Drop terms or use OR if you need to Broaden your search. Example:
A search is too Narrow if you don't get enough articles returned after you search. You need to Broaden it to get more results.
A search is too Broad if you get so many results you can't find the best ones. You need to Narrow the search to get the best ones.
Narrow search:
* one resulting article
Broad search:
*10,000 resulting articles