run a strong spoon like a lever between where the lid meets the jar, all the way around until you hear a pop—that’s the air tight seal breaking—now its is easier to twist open
You don't have to death-grip the lid as tightly when there's actual grip. Just wrap one around the lid (thicker ones work better than the one in the picture), and voila! We always have some on a hook for random things like this.
when you go to twist off the cap, simply tell yourself that you have already opened the jar. it’s always easier once it’s been opened so it shouldn’t be hard.