The first thing to get started to learn SEO is to primarily understand what it is. If you don't understand the big picture behind this then you won't get what you are doing. You won't be motivated enough to learn the art of the SEO.
SEO is the process of manipulating what we know about Google's algorithm to our advantage. This allows us to grab valuable online real estate that's quite valuable depending on what niche you target. To better understand this think of a newspaper. People are willing to purchase newspaper ads because the newspaper is being read by thousands of people. So, the advertisers want those eyeballs on their offer. Because they will be able to make a potential return on investment. They can spend 500 dollars in advertisements and get 1000 dollars back in profit because of customers they acquired or whatever.
Google is like that newspaper but is significantly more advanced. It does way more then a newspaper could ever imagine doing. 90% of Google's business comes from adwords. Which is essentially digital ads on Google. This is because millions and millions of people use Google's search engine to search for stuff. So, Google can rent digital spaces and make a fortune from advertisers because they got access to a bunch of people that these advertisers want.
Google is a index. If you search "how to eat money," Google will try to give you the 10 most relevant websites related to your query. There's millions of websites out there. Yet, only 10 spots on the first page. When Google generates those results, that's the result of the algorithm deciding that those 10 sites are the most relevant sites out there. SEOs game the algorithm and make Google think that their site is relevant to the query so you rise higher in Google.
The algorithm can be manipulated if you know the variables behind that algorithm. And, they pretty much look at two things. On-Page and Off-Page. The algorithm will give higher priority to websites that optimize for the result that is being searched and it looks at the amount of quality links pointing to the site. Links is how you put your site to the first page of Google.
Google decided that if a site links out to another - it would be some kind of a vote to that site. If CNN decides to link out to example.com then example.com will receive link juice from CNN. If a bunch of popular sites link out to a site and it's about the keyword - Google decides that your site is relevant to the query that is being searched and places you higher in the ranks.
You can learn more about linkbuilding from these amazing threads.
http://www.blackhatworld.com/blackh...ch-engine-optimization-guide-dolla-dream.html
http://www.blackhatworld.com/blackhat-seo/black-hat-seo/781273-how-rank-quick-guide-newbies.html
http://www.blackhatworld.com/blackh...w-comp-keywords-google-page-1-30-45-days.html
http://www.blackhatworld.com/blackh...ill-playing-tier-1-tier-2-like-kids-read.html
http://www.blackhatworld.com/blackh...t-ranking-methods-working-atm-not-newbie.html
The purpose of manipulating the algorithm is because there's money in it. If advertisers are willing to pay money to Google to rent a spot in "example keyword," then a SEO can make money from it as well. There's a reason why advertisers pay 30-50 dollars a click in competitive searches such as lawyers and insurance. That's because there's money to be made. Same thing with SEO.
Hopefully, you now understand the point of SEO and you read those threads to learn more about SEO. SEO is one way of obtaining traffic to your site. And, there's a whole range of things to learn to rank higher on Google.
Then you put all that information to test. Actually practice what you learn. This will allow you to speed up your learning. Nothing is better then your own experience and data.
The first thread you should read is the "How To Rank Guide" by Lightningblitz. Good stuff for newbies and advanced people. That will get you started in your SEO journey.
