Remove the screw
Clean out the hole
Insert a larger screw
Use a longer screw
Fill the hole with wood glue and toothpicks
Let the filler dry completely
Reinsert the screw
Use a wooden dowel and glue for a stronger repair
Drill out the hole and install a threaded insert
Use a wall anchor for drywall
Use a toggle bolt for hollow walls
Apply epoxy and re-drill the hole
Replace damaged material if needed