Microdata can make a very big difference for regionally- or locally-targeted sites. It's not a huge help otherwise. Proper use of ARIA landmarks and roles can also help a search engine make more sense of your site (as well as helping to make it accessible to a wider audience). But no matter how you break it down, the thing that makes the biggest difference to search engine results is to have something worth searching for or linking to. "SEO friendly" really doesn't mean much -- "SEO friendly" URLs do far more for humans than they do for machines. (The only useful thing that putting consideration into URLs will do for you is making sure that a search engine crawl won't harm your site; don't do anything with GET requests.) Any hints or tips that can't be summarized with the phrase "improve your content and accessibility" are short-term at best, and probably nonsense.