What you need:
Glass vessel. I bought this one at the dollar store. I say "vessel" because you could use almost anything: a mason jar, bowl, vase ...
Moss/Ground Cover (that's totally optional but you could probably find some outside if you wanted to use it!)
Rocks or Rounded Glass
Optional items: Sand. Activated charcoal: if you use this place it on top of the bottom layer of rocks).
What you do:
Place a good layer of the rocks or the glass at the bottom of your jar.
Optionals here: Place the activated charcoal on top of the rocks/glass then place a 1/2 inch layer of sand on the top of rocks/glass. (I used soil and sand and placed the sand on the glass pebbles and then placed the soil on top of the sand)
Add soil. I mixed in a few of my rounded glass pieces to further help arriate and I just had a few left over. You can add as much soil as you like. It really depends on if you want your succulents submerged in the vase or if you want them to stick out the top a little bit. I went for something in between.
I started placing my succulents in the soil and then cushioned it with the ground cover as I went along to give the top a nice greenery as well as to make sure my succulents were kept in place.
Water every 2-4 weeks and keep in partial shade. If you find loose leaves you can place them in soil and they will sprout and grow new plants! And then you can make more and give them as gifts to all your friends!
I love these little terrariums for simple, year-round centerpieces. I have also seen them used as centerpieces for wedding tables and it looks really beautiful.