Pinch Harmonics?

So, I am working my way through Rock Fundamentals 2 and I can not figure it out how to do a "pinch harmonic." I've even tried watching a few You Tube videos and I just can't get the sound everyone else seems to get. Is there some special trick I am missing here? Any good videos or ideas out there? How important is this if I just can't seem to master this?

Thanks for your help! This is just very frustrating, especially when I feel like I've been on a real roll lately with my guitar playing. 

Same here. Is there a lesson specifically addressing pinch harmonics? I feel like there is something everyone assumes we know about the technique that isn't obvious. Is it about amp settings that no one mentions because I can get a harmonic response like you do on an open string at the 12th fret but it doesn't have that squeal.

Yes, these are the lessons: 

https://www.guitartricks.com/lesson/21459

But no offense, I don't think he does a very good job of explaining how to do this technique. With that being said, I've watched 2-3 other Youtube videos and I still can't get that "harmonic response" either. Ha...maybe my thumb is too skinny or fat? 

It helps to have a least a little gain on your amp.  Also, use the bridge pickup.  Next, the technique is essentially creating temporary harmonic node with your picking hand thumb.  Choke up on the pick so that you can lightly graze the string right after you pick it.

Have a look at this lesson.

https://www.guitartricks.com/lesson/14117

Hope this helps!

Yes, it does take a bit of practice to get it (I'm still plugging away at it).   But Christopher's mention of gain is a good one - makes a big difference and easier to achieve.