By clicking on any keyword you get to know the pages ranking for it. This can then be used to ensure that you are targeting the same page for those key terms and are not directing your SEO efforts on other pages that may lead to cannibalization.
Also, from the HTML errors report - make sure that the pages having duplicate/short/long title and descriptions are fixed. This will help in better optimized site. Also, try and correct the link pointing to 404 pages. These things surely add to the efforts in a better optimized site.