Exactly how search engines locate and index web pages can be quite complex, partly because each search engine goes through a slightly different process. However, in general terms, search engines use special software robots called 'spiders' to crawl the Web and look for Web sites and the words contained in them. They also allow web page authors to submit the URL (address) and a description of their site for inclusion in the search engine's database.

Search engine spiders may take into account the words appearing in the title of the page, the words in the sub-headings and links in the page, and the URL of the page. They may also look at the 100 most frequently used words in the page, each word in the first twenty lines of text, the links to the page from other web pages, and the page's meta tags (keywords hidden in the code of most web pages).

When you type in the keywords of your query, the search engine looks at some of the above information (depending on what criteria they use) and decides which pages will be relevant to your query, and of these pages, which ones will be the most relevant.

In addition to knowing how search engines operate, it is also useful to know a few basic search strategies to employ in your quest for information. The most important thing to do at the start is to read the hints, tips or help section of the search engine you are using. This will tell you the best way to input your query in order to retrieve the most relevant results. Some search engines will require you to use capitals or quotation marks or other features for more effective and efficient searching.

As a general guide, try the obvious first. If you are looking for information on beagles, typing the word 'beagle' or 'beagles' is going to get you better results than typing the word 'dogs'. Use words likely to appear on a site with the information you want ('backpacker accommodation australia' rather than 'places to stay australia') and make your keywords as specific as possible ('white water rafting colorado' rather than 'water sports america'). Learning how to type your query effectively will save you a great deal of time and frustration.

For more a more detailed account of how search engines work, see the following Web site:
How Search Engines Work