Canadians, save $50/yr on the premium version of Yoast SEO
The free version of Yoast SEO is pretty good, I must admit. It allows you to optimize for a keyword by giving you access to the title and description meta fields. The plugin also allows you to optimize for Twitter and Facebook, which is another cool bonus. In addition, you get an XML sitemap which can be added to Google Webmaster Tools or Bing Webmaster Tools. Doing so gives the search bots a deeper look into your website to help determine how relevant and unique the pages are, which in turn helps boost your search ratings.