Development on Drupal Commerce is a community effort, and all are invited to join in where possible. We're bringing together people from around the world with a wide range of expertise to make this a giant leap forward in Drupal based e-commerce.
In order to dive in, you should know where the code currently stands and how to contribute to it. To that end, we'll be adding a project roadmap in the near future that ties into both a specification and issues in our issue tracker to visualize what we have completed and what remains to be done.
When you're ready to dive in, you should review the development standards and make sure you understand the Drupal Commerce code workflow. Then go pick an issue, find other people working on the same system, and get to work!