When planning a website, it is important to be aware of the existing competition. How are those websites attracting visitors? What do you like or dislike about those sites?
The following tools will help you identify and assess competing websites.
Alexa is a great tool to identify and learn about your competition. Simply type in the URL of a site and see how it ranks!
This webmaster tool will let you see which sites are linking to a given website (i.e. backlinks).