Making sure your information is getting to search engines and contains your most important information is vital to your SEO. It's important to clean up your data and focus on creating a site that is easy to be read and ranked by Google, Bing, and all the rest.
Creating a site that ranks is about creating a site that is useful for people who use the site. Knowing where to put your most important information can have a huge effect on how people use your site, and how search engines view your site's usefulness.
Search engines use a lot of data to decide whether your site is valuable and trustworthy. One of the most important ways to prove your site's value is to gather backlinks and citations on other websites to show how your content is trusted by others.
It's impossible to know how successful your work is if you don't measure success. Focusing your attention on the most important metrics will help you define your performance, and will educate you on your strategy's strengths and weaknesses.