While working for ethology I did SEO planning for Comlax.com, the sister site to Pure Hockey.
The client had been a customer for a year. No SEO work had been done on the site. The reason was because they had a design company that did not want to make the changes we suggested.
The client was not able to properly argue the need for the changes we suggested. I created a detailed report on what changes were needed and why they were needed. Then I went through the report with the client making sure they understood all the changes I suggested.
The client was able to convince the developer to make the changes and the client saw a 15% increase in traffic over the next 90 days.