Apply penetrating oil and let it soak
Use the correct size socket or wrench
Tap the tool onto the bolt head for a tighter grip
Try a bolt extractor socket
Use locking pliers if part of the bolt is exposed
Heat the surrounding metal carefully
Strike the bolt head with a hammer to help break corrosion
Cut a new slot in the head and use a flathead screwdriver
Use a left-hand drill bit to back it out
Drill out the bolt with progressively larger bits
Use a screw extractor
Weld a nut onto the stripped bolt
Remove the surrounding part if needed for better access
Replace the bolt after removal