tips for opening the lids of hard-to-open jars

If you have rubber grip pads to help with opening jars, don't only use them on the lid. Place another in your other hand which is holding the jar, or place one under the jar while pressing the jar against the counter while twisting the lid with the other pad.

Even if you use some other tool to twist the lid of the jar, it still helps to have a rubber pad to hold the other end of the jar in place, or to help twist the jar in the other direction at the same time.

Rubber foam shelf liners work well as rubber grips.
Rubber-coated work gloves work well too.