One of the best tools to check how well a page is optimized for a particular keyword is the Moz On Page Grader Tool.
All you need to do is to enter the URL and the keyword you want that page optimized for , hit the "Grade on page optimization icon and the tool will give you an overall grade based on your optimization efforts for that keyword on the page. They take a lot of important factors into account including:
- Rel Cannonical Usage
- Page Title
- Accessibility
- Keyword usage in the document
- Content Length
- Links
- Header Tags
It's such a powerful tool. You can basically run this tool for the top 10 URL's ranking for your target keyword and see how the competitors are faring on this tool and what you can do to improve your position.