I currently am working at skinnyskinny in Brooklyn. We have been working on expanding our plant section and one of my favorite parts of my job is making terrariums!
I can't tell you exactly how we make them or the plants we prefer to use. However, About.com has a great article on making terrariums at home: http://containergardening.about.com/od/floweringcontainergarden/ss/Terrariumht.htm
The little succulents have such character! I love creating these miniature worlds.