Tips for Managing Drupal 8 projects with Composer
It's been over a year since Drupal 8.0.0 was released, and the entire ecosystem has improved vastly between that version's release and the start of the 8.3.0-alpha releases (which just happened a couple weeks ago).
One area that's seen a vast improvement in documentation and best practices—yet still has a ways to go—is Composer-based project management.
Along with a thousand other 'get off the island' initiatives, the Drupal community has started to take dependency management more seriously, by integrating with the wider PHP ecosystem and maintaining a separate Drupal.org packagist for Drupal modules, themes, and other projects.