I wish I had this guide when I started looking into SEO about 6 years ago.. But it’s still good if you are a beginner now:
http://guides.seomoz.org/beginners-guide-to-search-engine-optimization

UPDATE!
When you are done, you could try to take this test and see if you can answer anything! 🙂 Don’t cheat!
http://www.seomoz.org/blog/answers-to-the-seo-professionals-litmus-test