If a query results in only a few hits, you could try the following options. First, you can reverse the methods to narrow queries, such as searching for fewer terms, not using the minus sign, quotation mark or the site-command. Besides, it is possible to search for synonyms and similar terms.
Searching for synonyms
A specific term which is not used often, will probably lead to just a few hits. You could try to include a synonym or similar term with the operator '|' (vertical bar). For example, you would like to know more about a letter of comfort, but you are not satisfied with the results. In this case, try the following:
"letter of comfort" | "comfort letter"
With this command, you can perform queries in different languages too:
"letter of comfort" | patronatserklärung