If you haven't already tried, you should read up on search operators & take advantage of it.
Google supports several advanced operators, which are query words that have special meaning to Google. Typically these operators modify the search in some way, or even tell Google to do a totally different type of search. For instance, "link:" is a special operator, and the query [link:www.google.com] doesn't do a normal search but instead finds all web pages that have links to www.google.com.
There are also some undocumented operators listed in the Google Guide. Some of these operators may work in other search engines as well.
Search operators for GMail are also available.
Also see:
Search Engines in the pre-Google era
Search Engine Wars