Maybe do seasonal themes. Working with amateurs can be challenging, so one type of project at a time as people might not be adept at using materials foreign to them. Cardboard, foam core, scrapbook paper, glues, mod-podge, paint are a great way to start as an introduction to basic skills. You can always offer a higher skill/materials level later-wood, plastics, polymers, casting bricks, etc. Photography and lighting are also a real option!