1. Each controller action only calls one model method other than an initial find or new. (Make custom .new or .update methods in the model with all necessary). …
2. Only one or two instance variables are shared between each controller and view. …
3. All model and variable names are both immediately obvious (to a new developer) and as short as possible without using abbreviations. …
4. All custom “finds” accessed from more than one place in the code use named_scope...