I recommend this article from the guys from Code Climate, it is really mind-opening: http://blog.codeclimate.com/blog/2012/10/17/7-ways-to-decompose-fat-activer

I recommend this article from the guys from Code Climate, it is really mind-opening: http://blog.codeclimate.com/blog/2012/10/17/7-ways-to-decompose-fat-activerecord-models/ http://blog.codeclimate.com/blog/2012/10/17/7-ways-to-decomp... The author describes different ways of refactoring fat ActiveRecord models, but most of the ideas can be used outside ActiveRecord, as "best practices". I have been using some of the patterns described in it and I am really happy with the results. The code becomes more clearly decoupled, is easy to test and results in clean, slim models.