Exact Phrase in Quotes " ": put quotes around your search terms -- "Bill Gates"
"+" search: Google ignores common words and characters such as where, the, how, and other digits and letters which slow down your search without improving the results. If a common word is essential to getting the results you want, you can include it by putting a "+" sign in front of it. (Be sure to include a space before the "+" sign.) -- Star Wars Episode +I
Domain search site: search only within one specific website by entering the search terms you're looking for, followed by "site:" followed by the domain name. leopard site:www.apple.com
Synonym search ~: search not only for your search term but also for its synonyms, place the tilde sign ("~") immediately in front of your search term.
Word definition Define: get definitions of a word -- define:bamboozle
Weather forecast Weather: get weather forecast by typing weather:zipcode or weather:city,state -- weather:98052, weather:redmond, wa
Conversion: enter the conversion you'd like done into the Google search box -- 2 inches in centimeters , or 3 USD in Euros, or 5 lbs in kg
Package tracking: want to find the status of your fed-ex package? or UPS? or USPS? Parcel tracking IDs, patents and other specialized numbers can be entered into Google's search box for quick access to information about them. "1z9999w99999999999"
Stock Quote: Just type in the stock symbol -- aapl
Flight Status: Want to check flight status? Type in the airline and flight number - BA 49
For more search help check out the "Google Guide" - an online interactive tutorial and reference for experienced users, novices, and everyone in between.