Some thoughts off the top of my head would include the following.
1. You need to realize the odds you're up against in almost all cases. Take any keyword or keyword phrase and you'll invariably be told at the top of the Search Results page that ....millions of related sites have been found. Given this, it's perhaps a miracle that your site is included at all!
2. The "magic" of
SEO lies in its ability to get a site among The Top Ten (i.e. on page one), Twenty, Thirty, whatever. And this is much, much, much easier said than done.
3. Undoubtedly, there are tricks to it, but this is in the good sense of the word (i.e. White Hat) rather than the wrong one (i.e. Black Hat). Moreover, there's an ongoing learning experience and you can never take anything for granted. On the one hand, your competitors today can increase/change tomorrow. On the other hand, the search engine algos are also in a state of constant flux, which means that what works today may fail utterly tomorrow.
4. Perhaps most of all, you need to avoid jumping to any quick conclusions. You need to study, analyze, and thoroughly think through anything you observe or suspect. It's perhaps fair to say that people who do know
SEO know enough about it to know that they'll never, in fact, know enough, let alone everything it entails!
Duncan