Run the lid under hot water for 30 to 60 seconds
Tap the lid edge gently with a spoon
Use a rubber grip pad or dish towel to twist the lid
Press the center of the lid to release any vacuum if possible
Slide a butter knife or spoon handle under the lid edge to let air in
Use a jar opener tool or rubber gripper
Ask someone else to try with better leverage
Wear rubber gloves for extra grip
Warm the lid with a hair dryer for a few seconds
Strike the lid edge lightly against a countertop while holding the jar securely
If needed, use pliers or a strap wrench on the lid
Avoid forcing the glass jar itself to prevent breakage