Google uses an algorithm for ranking its web pages known as PageRank and analyzes page content using Hypertext-Matching Analysis. The higher the PageRank the more important the page is deemed to be. According to Google, this algorithm includes over 500 million variables and 2 billion terms, and is changed frequently. A few key aspects Google deems important are:
When the Googlebot spider scans web servers on the the Internet, it creates an index and reports back relevant findings. While retrieved search results will not surpass 1000 items, currently 2,670,000,000 items are consulted in one form or another. The graphic below displays the step-by-step process taken when conducting a search.
"Life of a Google Query" http://www.google.com/corporate/tech.html
Search engines are not yet capable of understanding natural language, or semantics. Moreover, Google does not know what you are inferring. Are you looking for a bass guitar? Or are you interested in fishing for bass? As a result, every word that you include in your search matters.
When you perform a search, you must think in terms of strategy. For example, what nouns, verbs and/or adjectives express the results that you are trying to arrive at? One useful approach to developing this strategy is to create a mindmap. Mindmapping is essentially an analysis of your subject. Below, I have created a mindmap for a search on Federico Garcia Lorca, the great Spanish poet.
Finally, keep in mind that your search will be processed using boolean algebra. Normally, when you consult a database in advanced mode, you will see the options and, or, and not next to the text entry boxes. In basic mode, Google always applies the "And" operator. In Google's advanced search mode, the boolean operators are more apparent. To see how boolean operators are used in constructing search queries, watch the presentation below. In short, the And function is inclusive, the Not function substracts, and the Or function takes into account similarities.