I would also recommend two of Steve Klabnik's articles: http://blog.steveklabnik.com/posts/2011-09-22-extracting-domain-models-a-practical-example http://blog.s

I would also recommend two of Steve Klabnik's articles: http://blog.steveklabnik.com/posts/2011-09-22-extracting-domain-models-a-practical-example http://blog.steveklabnik.com/posts/2011-09-22-extracting-dom... and http://blog.steveklabnik.com/posts/2011-09-06-the-secret-to-rails-oo-design http://blog.steveklabnik.com/posts/2011-09-06-the-secret-to-... Another excellent resource is Gary Bernhardt's "Destroy All Software" screencast series. They are well worth the $9/month pricetag. https://www.destroyallsoftware.com https://www.destroyallsoftware.com