If you are a beginner then you can simply start with On-Page optimization which includes different activities like Meta Tag Optimization, Keyword Density, Unique Content, Link Structure, XML sitemap, etc... after completing On-Page Optimization start various Off-Page Optimization activities like Web Directory Submission, Article Submission, Blog Commenting, Forum Posting, Social Media Marketing, Web 2.0 Profile Creation and more.
First read out basic knowledge of SEO. And after that start doing practically on website or you can also done SEO Course from institutes or coaching centres.
If you are really SEO lover, Search in Google and you will came across many blogs and forums describing it in detail. Learn thoroughly and implement it in the website.
If you are just starting out start with doing good keyword research and putting quality content on your site. Try to target "long tail" keywords (3 words or more)
Start reading articles about SEO, looking for good blogs like this one to learn SEO, ask questions and read other people's replies! And then... Just try everything you think could be helpful for your website!
I would like to suggest Google as best tutorial for learning SEO. A few thinks you must now are Introduction about SEO Keyword Usage Off page optimization Onpage Optimization Keyword research Web analytics tool.
there are many online SEO tutorials available on youtube. Type seo tutorial in youtube i m sure you will get enough tutorial.
All the answers above are great and the only thing I'd add is that if you are using a web search for resources about SEO make sure that you use a site that has been updated very recently - search engines, especially the major ones, go through updates in how they prioritize websites and you want to make sure your SEO resource updates their information after each major update. (And even if you are going to learn SEO off line - such as taking a course local to you or something - ask whether the instructor knows the latest major updates to the big search engines.)
Download Google SEO PDF and start learning. Also get some great resource on MOZ, SEARCH ENGINE LAND, SEARCH ENGINE WATCH ETC. Let me know if you have more questions.
Two great places I would recommend are Moz's Beginner's Guide to SEO and the DistilledU "school" for SEO (I think they opened up quite a bit of it to be free now. Hope that helps!