Check out RailsCasts [1] by Ryan Bates. I learned RoR through the Ruby on Rails Tutorial [2] by Michael Hartl (highly recommend it). I then used RailsCasts to teach me specific things about practically everything. There are over 400 screencasts so that should keep you busy for a while. My general workflow would be to plan the feature out, watch the RailsCasts episode, and then implement the feature.
Hope this helps.
[1] http://railscasts.com/
[2] http://ruby.railstutorial.org/