,

1. Think in some interesting project, and build your module,
2. If you didn't, create a Drupal user, and a new sandbox for your module(s). Follow this instructions and commit your first lines of code http://drupal.org/node/1068950
3. Work in your project, and when you are happy to publish your first stable release, go to the next step.
4. Help the community, doing some reviews of other modules (3 at least): http://drupal.org/project/issues/search/projectapplications?status[]=2&status[]=7 (more info here: http://drupal.org/node/1410826)
5. Create a new project aplication: http://drupal.org/project/issues/projectapplications