After thinking about my session at PubCon yesterday and if we as a group of panelist (Mark Jackson, Lyndsay Walker Blahut, Aaron Wall, myself and our moderator Todd Friesen) had one thing we were trying to stress I cam up with the following. "Get in the project plan!"
Once you strip away the advice on how to and why you should use h1 tags, why writing good description meta tags and why using clean & valid XHTML is important, it really boiled down to you need to make the whole SEO process part of the project plan and part of everyone's deliverables.
You can't let the graphic designer get approval on a design that can't be marked-up in an SEO friendly way. Just the same as you can't let the html developer, the server management team or the back-end database programmers get away with it either.
So how do you do this, the answer is simple, but it is the execution that is hard. Step 1, get everyone educated on search engine optimization, how it works, the impact of different components on SEO and why it is important to your organization. Next make it part of each persons project deliverables. If their deliverable is not SEO compliant, then they haven't finished their job and need to go back and get it right. Of course, this means allowing enough time (budget if you are outsourcing it) for them to get it right. Just because it looks good or works from a technical point, doesn't mean it is. None SEO compliant feature must be treated as a web site bug and fixed on a high priority basis.