Grind the upper edge of the strike plate if the latch hits too high. This will remove some of the metal and allow the latch to catch without having to alter the placement of the plate and leave holes. Remove the metal to slightly above the chalk or lipstick latch mark.
Tighten the hinge screws if the latch hits too low. Likely, the problem is a sagging door and by simply tightening the screws, you should be able to alleviate the problem. If the door continues to sag because of stripped screw holes, remove the hinges, fill the holes with wood filler or broken bits of toothpicks and replace the hinges for a tight fit.
Chisel some wood from the strike plate hole if the latch hits the intended area. If the hole is not deep enough, the latch might not grip allowing it to easily slip out of place.