I've been helping two of my clients (Travel Guide to Vietnam and www.urbanthier.com) with SEO. It appears to be a full time job, writing content, understanding the analytics and improving them, working with google adwords.
These are two different businesses, City Pass Guide is the premier travel information provider for Vietnam and Urban Thier is a Law Firm in the US that is specialized US, German, and Brittish law, as well as other areas.
I'm learning a lot about SEO, but realize there is no magic bullet. It mostly boils down to good content at the end of the day.