How SEO companies Improve Page Ranking in Google?

• Social Media Bowling.  Get content on high-profile social media entities to "knock-out" out others on SERPs on certain keywords
• Choosing the right content/topics - High KEI
• Social Media Bowling.  Get content on high-profile social media entities to "knock-out" out others on SERPs on certain keywords
• Choosing the right content/topics - High KEI.  Or in other words, not focusing on the head-terms, nor the long-tail, but somewhere in the fat-middle.
• PR/Media - (link-backs from authoritative sources)
• Developing user generated content schemes/mechanics that is relevant and have value-add (Q&A systems, "knowledgebase", digg-like features, comment moderating/monitoring, forums, user-profiles, etc) 
• Internal cross-linking keywords to spread Page rank