Apply penetrating oil and let it soak
Tap the bolt head lightly with a hammer
Use the correct size wrench or socket
Increase leverage with a breaker bar
Try tightening slightly first, then loosening
Heat the surrounding metal carefully
Cool the bolt after heating if needed
Use an impact wrench or impact driver
Clean rust, dirt, and debris from the threads
Apply rust remover if corrosion is severe
Use a bolt extractor if the head is damaged
Cut the bolt off if it cannot be removed
Replace the bolt after removal