
You need to visit fairs and see and handle as much (properly identified) glass as you can. Visit studios and watch the masterglassmakers at work. Talk to people who might know stuff.
Learning as much about glassmaking as you can, does give you a good idea of what is easy or difficult to achieve, which helps you to judge quality.
There's really nothing can substitute for getting your hands on the glass and getting an idea of how it feels.
Lots of modern Chinese glass finds its way into stores such as TK (or TJ) Maxx, it's a good idea to pop into one of those regularly, to see what is for sale there.
The fact that this vase seems a bit lopsided and the bubbles are not well controlled should have been big warning signs that this wasn't Venini.
But if you don't know that to start off with, how are you to tell?

It still looks pretty good and the label fooled you too. That was deliberate and wrong.
I just hope you didn't pay a Venini price.