In your view you need to include the error_messages_for method. This takes a string argument that is the name of an instance variable.
in contoller
@thing.save #=> fails due to errors
in view
error_messages_for “thing”
You can have as many calls to error_messages_for as you want in one view, for as many instance variables as you have.
The docs as www.rubyonrails.org/docs have more in depth explainations.
http://api.rubyonrails.org/classes/ActionView/Helpers/ActiveRecordHelper.html#M000460
