The basic SEO things are: Article Submission Directory Submission Forum Posting Social Networks Log in creation ( Facebook, Linkedin, Twitter, Myspace) and More Services. Blog Commenting Blog Creation Blog Submission Link Building Website Analysis Competitors Analysis Keywords Analysis Title Tag Optiization. Do you know more?
Some of basic SEO are: Search-friendly URLs Avoid Flash Image descriptions Proper Use of the ALT Attribute. Quality of Inbound and Outbound Links Site Usability
I recommend tagging posts because thanks to them Google can find similar posts. You'll also get more internal links linking to your blog posts. I made my own auto tag plugin that handles this job for me. It saves a lot of time.
Readers friendly regular update contents are is best for SEO. It's a traditional golden rule for every webmaster.