Glassblowers Guide is built entirely around saving you time and money in the hotshop.
-Click through to YouTube for easy access to various sections of the video-
...or an hourglass, or a cooling tower. Whatever you wanna call it, this video covers 3 different ways of making forms with a waist. Tricky to get right, but it's a wonderful feeling when the bubble drops out into a perfectly smooth line.
If you want to learn these fast, practice them like you see in the video. Smallish, clear, and not puntied up. It should take less than 5 minutes to get to that point, so in a very short amount of time you can get a lot of tries at figuring things out!
Intro - 0:00
Method 1 explanation - 1:02
Method 1 demo - 1:26
Method 2 explanation - 4:24
Method 2 demo - 5:14
Method 3 explanation - 9:01
Method 3 demo - 9:48
Wrapup - 11:32