Here are some great discussions about SEO practices and tools, to help you get started (in no particular order):
Why Bieber SEO Copywriting Sex Doesn’t iPad Work Minecraft - A nice discussion about problems with the entire SEO process, especially in a competitive market, and why there are no magic bullets.
Local SEO: 10 Tips for Ranking in Your Area - Simple techniques to make sure you cover if you are marketing a local business.
Blog SMO Guide: How to Apply Social Media Optimization to Your Blog in 33 Steps - For most businesses today, social media needs to be a part of the overall SEO strategy. Here's a comprehensive set of tips and tricks to get a content-oriented site in shape for social media marketing.
What Small Business Clients Need to Know About Keywords and SEO - Basic keyword tips for small business SEO.
Which reminds me, SEOMoz Blog, is a one-stop shop for all kinds of SEO advice and deep articles.
The 20-Point SEO Account Takeover Checklist - Good reminders on what you need to get started with a new SEO client.
Which also reminds me, SeachEngineLand has a resources page with a fairly comprehensive list of starting points for learning about SEO.
SEO Tips For Website Owners: Running Your Website Like A Library - Nice, simple explanation of comprehensive SEO with a library metaphor.