People who use Drupal for any length of time reach a point where they become capable of answering questions for other users. Helping out in the forums, writing up a case study describing how you used Drupal, or joining the documentation team and helping to write the handbooks are all ways that non-programmers can contribute to Drupal. By giving support to other users as time allows, you help to keep the project moving forward. Contributing back to the community also allows you to begin building a network of contacts within the community, and these contacts can help you as your needs become more complex.

For a starting point for how you can get more involved in the Drupal community, see http://drupal.org/contribute.