Google Webmaster Tools is available free to all webmasters who have registered a site with Google. The tools can be used to monitor your site’s efficiency, check for errors, show you what needs repair and help you optimize for best usability and traffic.
First on the list is Google Webmaster’s error report – this will show errors like non-followed URLs, broken links, un-crawled areas of your site, etc. This can help you see which links are not working or that point to pages you have retiresd, and also shows you what pages are not being indexed.
The site defaults function lets you tell Google whether you want your page shown with the www or without. It also enables you to use geographic targeting, and activate image labeler so your images will show up in image searches.
You can obtain a list of URLs with duplicate title tags or duplicate meta descriptions, as well as find out if some of the ones you have are too short or too long.
You can find top search queries in a number of locations, but having this available in Google Webmaster Tools is just another plus. You can see what people are clicking on, and your ranking for each search term, as well as breaking it down by type of search (web, image, mobile) or by country.
You can manage sitelinks if you are lucky enough to get them – you may not be able to add pages on a whim, but you can ask that ones Google selects be excluded if you have the need.
These and even more features of Google Webmaster Tools are being added daily, so check out the options you have to improve your site even more!