What do you get when you cross an auctioneer with a Drupal developer?
The ability to rapidly develop in Drupal starts with a strong knowledge of the ~8k contributed modules. I highly recommend attending a local users group to learn the contributed modules. Short of that, I will help you up the learning curve into Drupal architecture by cherry picking some key modules you can't build with out. This will be a rapid fire talk with one minute spent on each module. Everyone will leave with a list of key modules to investigate.
Not to be out done by other presenters using the "45 modules in 45 minutes" title, I'm stepping up my game and going for 50 modules.
As of this post there are 8,581 Modules with 7.x compatibility versions but this is sure to change.