You may use Google search quite times a day. But unless you are aware of the tips of using Google search engine efficiently, you may get your desired result after much of wasting your time and after getting frustrated. You should bookmark this article of Google search tips if you want to profound with using Google search engine.

Quoting Phrases
Anytime you are interested in a specific phrase, such as a quotation from a speech, a song lyric, a line of a poem, or a book title, the best way to find it is by using a quoted search. When you place double quotes around a phrase, Google finds pages that contain the exact phrase.
    e.g.  "online marketing"
Rather then finding online and marketing as two separate words if searched without quotation marks.Similarly a whole quote or song lyric may be placed inside quotation marks to find them.

Exclude Terms 
If you do not want to include a specified term in your search results or want to prevent Google to search similar terms then use (-) "minus" symbol before term you want to exclude.
    e.g.    virus -computer
It   will  exclude viruses which relates to computer  and will only display results related to biological viruses.

Forgotten Phrase
You can find a complete phrase by substituting ** symbol within or without the quotation marks if you know the initial part of phrase.
     e.g.        "what is about **"   OR     "what is about" **
It may generate what is about to happen?, what is about to come?  etc

Related terms
You can search   terms that match each other or if an item is known by more than one term by using ‘'OR ‘' or  " ~ " between terms.
    e.g.   Wireless OR  wifi  OR  network,     wireless ~wifi
OR is helpful if spelling is not known or term has more then one variation or you want to include both singular  and plural forms of a word.
" ~ " give most relevant terms, synonyms or antonyms

Searching within or without a website
If you want to search a definite keyword within or outside the website then use "inurl:site"   command.
     e.g.  (1)  Within a site
                    data entry jobs   inurl:www.freelancer.com
            (2) Outside a site
                    data entry jobs -inurl:www.freelancer.com

By using (-) minus sign before inurl:www.freelancer.com you can search that term outside  http://www.freelancer.com/  .   Using above technique you can also eliminate duplicate product search result at a similar website.
    e.g.   -inurl:www.amazon.com , -inurl:www.ebay.com etc

Searching  file  types
If you want to search a specific document type for your search words then place the document extension at the end of the words.
   e.g.   For   pdf type   "searchwords .pdf" ,      for  powerpoint &   word type  "searchwords.ppt", "searchwords.doc" etc

Conversions
You can convert any currency ,reading or measurement  just typing "in "  between two quantities by using  google.The quantity which is to be converted is written before the "in"  and quantity to which conversion takes place is written after "in".
    e.g       100 GBP in USD , 50kg  in pounds, meter in  centimeter etc

Local time & Weather
Local time of any city could be find out by just typing "time in city"
      e.g.      "time in London"
Similarly weather of any city could be find out by typing "weather in city"
      e.g.     "weather in Montreal"

Searching within a range
If you want to search a query within a range of numerical values then just type ".." between two numbers. This type of search is useful for finding prices, events or any thing that relates to some numerical data.
           e.g.                     Laptop $400..$700
                                     Olympics  1954..1990

Stock
Type a valid stock ticker in Google search bar and it will give you the current financial performance and statistics of stock.
          e.g.    YHOO

Patent
Type in patent no. or name and write "patent"  after  it, you will find complete description related to patent.
        e.g.      986253 patent ,          Horse Pacifier patent