Step 1: Know a guy who knows how.
Step 2: Have him show you how.
Step 3: Display in your home and take all credit.
I've been wanting to learn how to make a terrarium for quite some time. My brother-in-law, Michael, works at a glass studio. Last time he was in town, he brought all the tools and showed me know. It's a dangerous job: the glass is sharp, and the chemicals used are poisonous, and metals are melting at high temperatures... but it was all worth it.
Thanks again, Mr. Glass, aka Samuel L. Jackson, aka Michael.