Creating, editing, and promoting unique high-quality content is difficult and time consuming. If you are really serious about SEO and you are not getting expected result then better choice is to hire an SEO expert. There are following tasks which should be taken care by SEO experts
Code validation and clean up - Ensure that code is SE Friendly and standards compliant.
Site Structure - Building a semantic structure/theme and ensure URL's are spider friendly.
On Page optimization - Page Title, copy writing, Call to action etc.
Quality...
