I have some magic words that seem to help. At least when I get to the point of saying them, the "sufficient leverage or force" seems to be at hand.

Getting the tire bead deep into the rim's "trench" is a good tip, as it frees up a few mm of slack. I do use my tire levers once in a while, but I run my finger inside and have the tube partially inflated so it isn't folding around in there.

I then inflate the tube to about 70 psi or so, listening for sounds of a pinch being forced out, etc. A lot of "snaps and pops" indicate you could have a lot of twisting or pinched areas on the tube. As soon as the 70 psi is reached, I deflate the tube, let it fall away from the sides of the rim/bead, etc. Then I reinflate. This takes about 20 seconds longer than simply inflating, and seems to work. If I'm not on the road, I repeat until I don't hear noises as I reinflate. I'll never know if it actually works, but I'm not getting pinch flats, basically.

My LBS changes tires quickly, as it's a customer service thing for him and no labor revenue. Once he started with the inflate/deflate thing, he's not had any pinch flats, either, and he's using a compressor, which makes pinch flats more likely, as the tube inflates before it can ease it's way out of the bead pinch.