If you want to narrow your search right off the bat, you can add a category when you type the term in the Search field.
For example, if you’re looking for a song named “Vertigo” (by the band U2), there’s no sense in having Spotlight bring you a list of email messages from your ear doctor, right? So if you give Spotlight a hint as to what you’re looking for, you can get just songs as your Spotlight search results. Here’s how: Type “kind:music” (with no space in between or quotations), then add one space and type “Vertigo” (again, you don’t need the quotes). So your search will look like this: kind:music Vertigo. Now it will only search songs, and you’ll only get song results. Schweet!