Use quotes to search for an exact phrase. “green buildings”
Use OR (capitalized) to search for sites that may use one word instead of another. Without the OR, the search defaults to AND and finds only sites that include both terms. buildings OR architecture
Use quotes and OR to search for either of multiple phrases. "green buildings" OR "sustainable architecture"
Add a dash (-) before a word to exclude all results that include that word; can also be used before a site to exclude results from that site. This is especially useful for words with multiple meanings, like green the color and green the environmental term. green buildings -paint | sustainability -site:wikipedia.org (this will exclude wikipedia hits)
Use site: to limit your search to a specific website or domain. “public health” site:cdc.gov (this will return hits only from the CDC website) | “public health” site:.gov (this will return hits from any .gov website)
Use parentheses to combine and search for similar terms. (green OR sustainable) (buildings OR architecture)
Use filetype: to limit your search to a specific type of document. "green buildings" filetype:pdf (this will only find .pdf files; other filetype choices include html, ppt, and doc; note that you can also exclude certain filetypes by using the dash before the word filetype)
Combine two or more of these for power searching. “(green OR sustainable) (buildings OR architecture)" -“new york” (site:.gov OR site:.edu) filetype:pdf
Google offers an advanced search that will let you build many of the features above, and a few additional limiters, into a form. In the bottom right corner of the Google home page, click on settings and then advanced search.
Another useful tip: after doing a Google search, your results page will include a menu across the top that includes search tools on the far right. If you click the search tools link, you'll get a secondary menu that includes any time, all results, and (probably) San Diego, CA. You can use the any time dropdown to find websites that have been updated within a given time period. You can also use the all results dropdown to select nearby, which will find websites geographically related to the location that shows in the time/results/location menu bar.