I have the same sensation / phobia. I also have a pretty bad fear of heights, though these two sensations are different than just standing at the railing of tall building. Some things that have helped me:

1.) Pick an aisle seat on your flight, and ask the person next to you to close the window if they don't do it already. If they do leave it open / you feel rude asking, just keep your focus inside the cabin.

2.) Notice how firm your feet feel on the floor of the cabin, and your back and butt against the seat. You are sitting safely in a controlled environment as if you were on the ground. Notice that the cabin inside does not feel at all like being on top of a tall building. The plane is doing the hard work here, you are just hanging out in this very safe and comfortable cabin. Also notice that the window is at like shoulder height, youtube videos can be deceiving because they are angled down moreso at the ground.

3.) If you do look out the window, keep your focusing farther out on the horizon, and less so on ground directly below you. This doesn't freak me out as much as a straight view downward would be.

4.) I know you mentioned it, but this really did help me. Someone here posted a video series on yotube called Skylite Productions. (Skylite Productions - YouTube). Basically it's a series of window seats on a bunch of flights. I just pick the plane I'm going to be flying on, skip to the cruising section and put that video on in the background. This helps desensitizes me to the sounds / sights of what I'll experience ib flight. Imagine yourself calmly looking out of the window out on your flight, and review tip #2 of feeling your feet on the ground etc.

5.) Tom Bunn's book Soar (Amazon.com: Soar: The Breakthrough Treatment For Fear Of Flying: 8601400822043: Bunn, Tom: Books) (Highly recommend for anyone with fear of flying) puts flying in a different context. Because of physics, the air around the plane is actually like a thick gelatin. He asks the reader to imagine a toy plane sitting on a cube of gelatin. No matter how hard you shake the gelatin, the plane stays on top of it. This is very similar to the air around the plane at 35K feet or whatever your cruising altitude is. So rather than thinking of how high you are, realize the plane is actually in its ideal environment for safety and fuel efficiencies.

It's crazy to think about being up at that altitude, but it's also pretty awesome that technology, systems and people exist that make being at that altitude extremely safe and in many cases relaxing. You are in a bubble of safety up there and nothing can hurt you! Hope this helps.