Drupal Commerce provides a lean core of commerce functionality, which is meant to be extended with contrib modules for common use cases. And these days, everyone is writing a Commerce module. Haven't started yours yet? Come learn how Commerce uses D7 technologies (entities, fields, the ajax and testing frameworks...) and contrib modules (Entity API, Views, Rules) to achieve an unpreceded level of flexibility. Learn about important patterns such as API/UI separation, building UIs with Views (including embedding forms), storing prices, price precalculation, etc. Then learn how to apply the lessons learned to your own code, especially if it is code that interacts with Drupal Commerce. In the end, see how a few of the existing Drupal Commerce contributed modules have incorporated some of those lessons. A basic knowledge of how Drupal Commerce works and what D7 brings to the table is recommended. Teaching you every mentioned technology from scratch would take more than a few sessions, the goal of this one is to connect the dots and provide you with an overview of things you need to know and the ways you could and should use them.