Search Engine Optimisation or SEO makes me frown. The zeitgeist has been that if you are serious about your online presence then you need a specialist SEO agency. I've worked on sites big and small alongside such agencies and have come to the conclusion that in most cases there are better places to allocate your budgets.
Google makes no secret that they work tirelessly to counter SEO strategies designed to circumvent their efforts to deliver worthwhile search results, and have no compunction at all to deal brutally with those using underhand methods. Want to lose your ranking? Then try link farming, or any one of the hundreds of 'sure fire ways to boost your position' that have fallen from grace over the years.
Repeated algorithm updates have sought out and destroyed every temporary advantage the SEO 'experts' have applied to websites in their care, and when they get caught out who pays? Not the SEO companies. Of course there are ethical SEO companies out there but when you analyse their proposition it's to build the best website you can... surely that should be taken as read?
Google has triumphed as the greatest search engine in the world on the basis of it's unparalleled search results; maintaining the quality of those results is paramount to this technological behemoth. Rather than try and beat it, go with the flow. Give your audience what they want, which is information. Google doesn't write content, it links to it, so to win at SEO you should feed the Santa Clara beast a diet of rich, useful and original content.
Yes of course you need to employ standards driven web design and yes you should do everything you can to demonstrate authority, such as linking your authorship, but as for the rest of the SEO trickery, you'll do better to think about how your site content can help your visitors.
Without content Google is nothing and they can't help but reward your original labours.