Know the terminologies and terms used in programming, not just those specifically used for Ruby on Rails.
Acquaint yourself with the various functionality of Ruby on Rails. Visit and explore sites that use Rails.
Know the basics of Ruby. Ruby on Rails is based on Ruby, and knowing its basics will help you with Rails.
Explore existing sites and applications that employ Ruby on Rails.
Be updated. Keep on reading on the latest trends, news, and updates about Rails.