Concrete advice for developers about SEO by Kate Mats.

• Make sure your site is crawable
• Use the right keywords in all the right places
• Avoid duplicate content
• Use smart meta descriptions
• Freshness
• Fast site speed
• 301s vs. 302s and site errors (like 404s)
• How to pick keywords

http://katemats.com/2012/03/04/what-every-programmer-should-know-about-seo/