Search educational sites only, e.g., philosophy AND site:edu
Search with phrases in quotation marks, e.g., "health reform" site:gov
Search within a specific website, e.g., DNA site:plos.org
Search with exact words when you don't need synonyms included in the results, e.g., +undergraduates
Things to Keep in Mind....
Personalization and Geolocation will affect the results of searches. Google will deliver results based on where you are. Try searching other search engines.
Prior search history and browser version will influence the results of the search. Browser version indicates to Google the sophistication level of the searcher.
Google results are influenced by searcher's implicit feedback such as: how much time a user spends on a page; scrolling; interacting with ads; frequency and time of day surfing the web; and data Google receives from user's different applications (IM, reader, e-mail).
Google results are also influenced by searcher's explicit feedback such as: bookmarking a page; checking like/dislike button; printing or e-mailing the page.
Google Scholar has recently added Google Scholar Citations tool allowing authors to track their cited works, create their profiles and connect with other researchers in the field. Google account is required to search the Google Scholar Citations. The following is an example of a scholar's profile.