If the messages in my email spam directory are to be believed, all I need to do to get on the front-page of google is to in some (undefined) way optimise my web site and that'll be that.

Unsurprisingly, this is mainly nonsense. There are, of course, steps that should be taken to enable the main search engines to find your content but the magic is really in the content displayed on those pages. 

If a site is posting regular, informative information about a subject, there will, somewhat of necessity, be words that will be referred to and used with great frequency. As a subject gets more and more specialised a topic-dependent set of acronyms and jargon will emerge. 

When a potential reader is trying to find specialised content, these same words and phrases will be used. 

SEO is a little bit about technology but it's a lot more about building and displaying domain-expertise. At the end of the day, search engines want to direct users to  pages that most closely match their needs. The engines are built to recognise technology hacks and reward timely, pertinent content.