A Visual Guide to Keyword Targeting and On-Page SEO

By: Rand Fishkin, On-page SEO, August 6th, 2013.
This is a challenging question for many in the SEO and web marketing fields. There are hundreds of “best practices” lists for where to place keywords and how to do “on-page optimization,” but as search engines have evolved and as other sources of traffic — social networks, referring links, email, blogs, etc. — have become more important and interconnected, the very nature of what’s “optimal” is up for debate.
Read more: http://moz.com/blog/visual-guide-to-keyword-targeting-onpage-optimization