As my graduation gift, I had my grandma (who was once President of the Missouri National Garden Club thank you very much) work on a terrarium with me to take to my dorm!
I now consider myself to be a bit of an expert (cough cough) so I can lay out the steps for you! So simple once you have all your stuff together, most importantly your terrarium (any glass dome/jar/mini-greenhouse is perfect) and small plants to put in! Succulents should be a priority.
You can also throw in fun little "accessories" that they sell in most nurseries close to the small plants or around large garden accessories (ie. flamingo's, duh). I picked out this sassy little lady (name ideas plz) and a mushroom!
This is the order in which you throw things into your terrarium^^^.
Voila! A perfect little home for sassy pigtail girl, her mushroom and her succulents/moss. My grandma also highly recommends mini African Violets (if you can find them, the ones we found were too big for this tiny space). Mist them daily, take off the lid when it gathers moisture and leave it off for about a day, and don't keep it in direct sunlight!