One thing that hasn't changed much is the importance of link building. This refers to the practice of having other, well-regarded sites link back to content on your site. The idea is that this will elevate your own site's authority and popularity in search results.
Think of a link to your site from a major company or blog as a vote of confidence in Google's perspective.
In this short video, Rand Fishkin, founder of online marketing and SEO firm Moz, explains more about what link building is and how you can do it right.