#1 All words
By using the AND operator, you can tell the SharePoint search query engine you want to make sure it only includes results that contain all of the words. Alternatively, you can use the + symbol.
Example: onespace AND ESS
Example 2: delegation AND authority
#2 Filename contains a specific term
By using the filename property restriction, SharePoint can find files that have a specific name. Using asterisk/wildcard character, you can find files that have a specific term in the filename. This property restriction needs to be first, and followed by a colon, then the search term in quotes. If SharePoint doesn't find an exact match, it will return results that have the term in the file name.
Example: filename:"Computer Tools.docx"
Example 2, files that have the word tools somewhere in the filename: filename:"*tools*”
#3 Exact Phrase
By using quotation marks, you can tell SharePoint you want results with the specified phrase returned.
Example: "delegation of authority"
Example 2, combining with the AND operator: "your department" AND "delegation of authority"
#4 Exclude words
By using the NOT operator, you can tell SharePoint you do not want any results that have the specified word. Alternatively, you can use the - symbol.
Example: communications NOT library
Example 2, combining with phrase search: "delegation of authority" NOT library
#5 Any of the words
By using the OR operator, you can tell SharePoint you want to results that contain any of the specified words. This can be especially useful in the world of acronyms we live in.
Example: SP2016 OR "SharePoint 2016"
Example 2: PowerShell OR "SharePoint Management Shell"
#6 Authored by a specific person
Use the author property restriction to find files where the author metadata matches a specific person. This property restriction needs to be first, and followed by a colon, then the search term in quotes. You may also need to use a wildcard at the end since some people have a middle initial or other characters at the end of their name, depending on how they are formatted in your organization.
Example: author:"Collogan, Vincent*"
Example 2, combining with OR operator to fine documents authored by either person: author:"Collogan, Vincent*" OR author:"Humberdink, Englebert*"
#7 Created or modified
Using the write property restriction, you can specify dates. By using 2 write property restrictions, you can return files greater than and less than certain dates, giving you a range. You can also use certain date intervals to restrict the results to those intervals. These include "today", "yesterday", "this week", "this month", "last month", "this year" and "last year", and they must be in quotes. The date(s) specified should be in the format yyyy-mm-dd (also knows as ISO 8601-compatible datetime format) and also need to be in quotes.
Example: write>"2016-12-31" AND write<"2017-05-16"
Example 2: write>"last month"
#8 On a specific site
Use the site property restriction to restrict results contained on the specified site. You can be specific down to the subsite, library or list level.
Example: "engineering management" AND site:"http://yourDomain/SharePointSite/Library"
Example 2: "staging" AND site:"http://yourDomain/SharePointSite/Library"
#9 A specific file type
You can use the filetype property restriction to return results matching the specified file type. While the refinements panel on the left allows you to restrict results to certain file types, you may find doing this straight from the query box is better. You can also use the OR operator to include, for example Word documents of both the old doc format and the newer docx format.
Example 2: filetype:doc OR filetype:docx
#10 Implement crawl best practices
This is not an advance search technique, but having SharePoint search properly set up will help ensure the best search results. Best practices for crawling in SharePoint Server 2016 (also links to other versions) https://technet.microsoft.com/en-us/library/dn535606(v=office.16).aspx
I encourage you to go and test out some of the examples I've given here and see what results you get. Then, hopefully, you can use those examples to help you find what you need.