The truth is that after I initially learned the gist of what SEO was and how search engines basically worked (which can be done by reading one or two articles, assuming you're familiar with the Internet), I learned the most not from SEO "how to" guides or anything, but simply from picking up neat SEO tips here and there, and then fitting them together myself into the bigger picture.
Pasted below are a few lists of tips I'm going to go ahead and recommend. Read what I've posted here, and even though none of them are a guide or a really in-depth look at SEO strategy, you'll still get a good idea about what good SEO really is.
General SEO Tips
Daily SEO Tip Blog (one SEO tip per day, everyday)
52 SEO Tips
Top 100 SEO Tips to Learn Search Engine Optimization
10 SEO Tips
20 Hard Core SEO Tips (these are pretty hardcore... but, uh, not that hardcore)
100 SEO Tips to Promote Your Site
55 Quick SEO Tips Even Your Mother Would Love
Link Building Tips
SEO Link Building Resources
15 Link Building Tips for New Websites
10 Link Building Tips
131 (Legitimite) Link Building Strategies
101 Link Building Tips to Market Your Website
(Oh, and here is a helpful YouTube rap about linkbuilding)
SEO Copywriting Tips
10 Tips for SEO Copywriting
14 SEO Copywriting Tips
20 SEO Copywriting Hints (Not tips - hints)
101 SEO Tips for Writers