Use the correct screwdriver bit and apply firm downward pressure
Tap the screwdriver lightly into the screw head to help it grip
Place a wide rubber band between the bit and the screw head for extra grip
Try locking pliers if part of the screw head is exposed
Use a manual impact driver to break the screw loose
Apply penetrating oil and wait a few minutes before trying again
Cut a new slot in the screw head with a rotary tool or hacksaw
Use a screw extractor bit
Drill a small pilot hole into the center of the screw and use an extractor
Drill the screw head off if necessary
Remove the attached part after the head is off and grip the remaining shaft with pliers
Replace the screw with a new one after removal