Use the correct size screwdriver and apply firm downward pressure
Place a wide rubber band between the screwdriver and the screw head
Try a larger flathead screwdriver if the screw is Phillips or slightly stripped
Tap the screwdriver into the screw head with a hammer for better grip
Use locking pliers if part of the screw head is exposed
Apply penetrating oil and wait a few minutes if the screw is stuck
Use a screw extractor bit
Drill a small hole into the screw and use an extractor
Cut a slot into the screw head with a rotary tool and use a flathead screwdriver
Use a left-hand drill bit to back the screw out
Heat the screw briefly if thread locker is present
Remove surrounding material if needed to access the screw better
Replace the screw after removal