Now you will only see those apple sites that also have the word green on them.  This will still give you about 16 million websites. But a lot of these websites are about apple computers.  To narrow the search even more eliminate the word “computers” by typing:  apples +green -computers"

We still have about 14 million web pages to check out.  A final way to narrow the search is to use quotes to narrow the search to an exact phrase.  For example if what we’re really interested in is granny smith apples we could type “granny smith apples” in quotes. 

This is called an exact phrase search and this is also how you catch a plagiarists.  If you see a sentence that you suspect has been plagiarized from the internet all you have to do is type that sentence into Google, in quotes, and you'll find the exact website that the text might have been copy & pasted from.

For more ideas to narrow your search quickly try these links:

12 Quick Tips To Search Google Like An Expert
      By Dharmesh Shah, March 5, 2007

15 Awesome Google Search Tips and Tricks
      By Sathiyamoorthy, June 4, 2009