I run a medical website on the drupal platform.
Ideally you would have several completed projects for drupal websites in your portfolio.
1) Theme customization
a) make user data entry pages cleaner
b) improve "About" page
c) fix pathauto problems
2) Get sendmail working on my server
3) Installation of vbdrupal (integrated vbulletin with existing Drupal website)
4) Setting up automatic backup procedures for database and web directories
5) Other improvements you think could make the site more attractive to users to reduce bounce rate.
This would be on a test site first, then on a full production site.
Show me sites you have worked on and I will show you the money!