Well, first of all thank you for reading the article. Second, where to learn SEO? It's a good question.
My wife just completed a certification course offered by webCEO http://www.webceo.com/ and it's amazing how much she learned. And how much I learned that I didn't know (and I have been in the biz for 15 years).
Other than taking a course like that or buying a book on the topic, a DIY solution is to join a few user forums where the topic is discussed and start following the threads. At first you won;t understand much, but using Google and doing some research in a short time you should learn a pretty good deal of stuff on the cheap.

However, my SEO philosophy can be summed as such:

1) There are no miracles. SEO takes time.
2) Target sub-categories if your area is busy (for instance, if you are in real estate, trying to gain ground on the keyword "real estate" is almost impossible, but "real estate Market St." is going to be a heck of a lot better.
3) above all, write your articles well. Your content has to be "keyword rich". But write them for your audience, not for the search engines.
4) Write a blog. It's amazing how many hits a blog on a specific topic can produce.
5) Change your content frequently. Meaning write often and write to inform your audience. The ranking will follow.
6) don't hire those that promise miracles. If you have the budget, by all means hire a professional. But they cannot do the impossible. If your homepage has a picture and a link that says "click here" the search engines will likely ignore you and a SEO pro can do nothing.
7) Learn to use Google Analytic or hire someone that knows it. You need a baseline so you can measure your progress. An SEO specialist will be most useful to do this kind of work. They still cannot write your articles or code your site (for the most part) but they can keep track of what works and what doesn't.

This is it off the top of my head. I can already see many more comments with "you forgot....!". Well, so I forgot. It's a vast topic with as many opinions as there are experts. The above is what came to mind writing this. If you have your own opinions, post them here. I may learn a thing or two.

Thanks