Google recently updated Webmaster Tools making it easiser for  marketing and business types to find great data to improve site performance.  The good stuff is under the tab Your site on the web.  Top Search Queries tells you the number of times your site appeared in Google search results ranked in order plus the percentage of those top queries represented by each query. So to begin with you are looking for the larger percentages. Next, to the right of the query term, is the Position that your highest ranked page appeared for that query. So if you are ranked low for a query term that has a large percentage of impressions that represents a good opportunity for more traffic for that term if you can get a better ranking.

Webmaster Tools Top Search Queries

Further to the right is the section headed Clickthrough. Here you can see similar data but  now for those who clicked through to your site.  First  look at the search query terms.  Are there any here that you did  not expect ? If you are gettings clicks from a term that you do not rank highly for and want more of that traffic then get working on that. Note that you can select the specific date range and region that you are particularly interested in.

Further down Your Site on the web is the Keywords menu. This shows ” the most common keywords Google found when it crawling your site “. This is great data when planning the next steps for your site.