As Drupal is moving to the localization server localize.drupal.org, here's a small tip that took me a little while to find, but can be very useful in the end, as it will allow you to contribute your translations back to the Drupal community more efficiently.

The problem

Let's say you install a module in your own Drupal website. However, this module is not fully translated for whatever language your website is in. You can, obviously, use Drupal's translation interface on your own website and translate from here whatever is missing.