Identify a phrase.

Before:	home run records
After:	"home run" records

The before query is ambiguous. Is it looking for the home page of songs like "Run, Run, Run" or baseball statistics? Identifying "home run" as a phrase eliminates the ambiguity. This is the most powerful query refinement technique.

Add a discriminating word or a phrase.

Before:	"home run" records
After:	"home run" records baseball

As before, the before query is ambiguous. Adding baseball makes the query less ambiguous. You'll get more total matches (because the query is broadened with an additional term), but the relevance ranking will be better.

Use a require or reject operator (+,-).

Before:	Barney
After:	Barney, +Smith -dinosaur

Barney alone is ambiguous. It it looking for Smith Barney investment information or cartoon dinosaur pages? You can use the reject operator (the "minus" sign) to eliminate the cartoon dinosaur interpretation. Or, you can require that the word "Smith" be in the document. The after version above does both.