Laurie in Lynn, MA, has been dreaming about making a graveyard-themed terrarium. After preparing some advice for her on how to get started, I totally want to make one, too. Here’s a great list of resources for how to get started (many of which could certainly be used to make terrariums that are totally unrelated to graveyards!)
Tips & Notes
It seems like there are a variety of not-terribly-in-depth graveyard-specific terrarium ideas online, but I suggest you start with plain terrarium information and tutorials, and add your own graveyard touches as you desire. Look for products and tutorials that will help you craft your own miniatures, or miniature graveyard.
Terrarium Building Tutorials
Books & Magazines
Gardening in Miniature: Create Your Own Tiny Living World, by Janit Calvo
Kawaii Polymer Clay Creations: 20 Super-Cute Miniature Projects, by Emily Chen (this might be helpful for making miniatures, if you adapt the projects to your graveyard theme)
You could purchase graveyard miniatures instead of making them yourself.
In the Lynn, MA, Area
Plant Nite holds terrarium-making events at pubs in Boston (not graveyard-specific, but pretty cool looking!)