WebSite Auditor scans pages for code errors, duplicate content and other structure-related issues they may have. Other than that, there is this on-page optimization module, which allows determining the ideal keyword placement and researches page elements that can be optimized. In WebSite Auditor you can also analyze competitor’s pages to compare of to improve own on-page strategy. There are actually more features, I just won’t be listing all of them here. But this is the best solution with regard to on-page optimization I found so far.
A variety of methods can increase the prominence of a webpage within the search results. Cross linking between pages of the same website to provide more links to important pages may improve its visibility. Writing content that includes frequently searched keyword phrase, so as to be relevant to a wide variety of search queries will tend to increase traffic. Updating content so as to keep search engines crawling back frequently can give additional weight to a site. Adding relevant keywords to a web page's metadata, including the title tag and meta description, will tend to improve the relevancy of a site's search listings, thus increasing traffic. URL canonicalization of web pages accessible via multiple URLs, using the canonical link element or via 301 redirects can help make sure links to different versions of the URL all count towards the page's link popularity score.
In Keyword Planner, formerly known as the Keyword Tool, you can get search volume and traffic estimates for keywords you're considering. Unfortunately, when Google transitioned from Keyword Tool to Keyword Planner, they stripped out a lot of the more interesting functionality. But you can make up for it a bit if you take the information you learn from Keyword Planner and use Google Trends to fill in some blanks.
I added one keyword to the page in plain text because adding the actual ‘keyword phrase’ itself would have made my text read a bit keyword stuffed for other variations of the main term. It gets interesting if you do that to a lot of pages, and a lot of keyword phrases. The important thing is keyword research – and knowing which unique keywords to add.
This broken-link checker makes it easy for a publisher or editor to make corrections before a page is live. Think about a site like Wikipedia, for example. The Wikipedia page for the term "marketing" contains a whopping 711 links. Not only was Check My Links able to detect this number in a matter of seconds, but it also found (and highlighted) seven broken links.