You won’t become one just by reading resources online.  There are many alright.  You can be choosy and cross your fingers you’re getting the right information.  But the internet abounds with both right and wrong information on just about anything.  Not even wikipedia is correct all the time.  And nothing is static; there are always new ways of doing things, especially among techies.

So how do you gain SEO expertise?  You need practice.  Just like attaining the master level in any video game, you need to apply the things you’ve read about and see if they work or not.  Try to get some web page development accounts and do the SEO magic you’ve learned and see how far up the Google returns it goes.

Or get yourself employed in a website developing or SEO company to get your hands dirty.  Until you can say you’ve developed a web page that is right on the first 10 or first return page of a search engine, keep on dreaming.