Google has released a new video featuring Maile Ohye from the webmaster support team, who talks about the "Search Queries" feature in Webmater Tools, and how you can use that to "improve your site".
The video discusses the vocabulary of the feature - things like impressions, average position (only the top-ranking URL for the user's query is factored in), click, and CTR. It also talks about steps for a way to investigate top queries and top pages.
Last month, Ohye spoke about site verification in another video. Watch that here.