If your door is failing to latch correctly it is usually an alignment issue. The first, and easiest, thing to try is to tighten loose hinge screws. If it still doesn't close correctly see the steps below for other remedies. Which one you will use depends on what you find the problem to be.

1. Step 1

   
   

    
   Strike Plates

   
   

   Figure out in which direction the latch bolt is off center. If it meets the strike plate above or below center, shim a hinge to change the angle at which the door hangs. This may solve the problem but it may make the door bind.

2. Step 2

   If the alignment seems okay but the door won't latch or has to be pushed to latch, the door is probably warped. This indicates a moisture problem and you should check the edges to be sure it is sealed correctly. At this point you have two choices:
   --Try to counteract the warp by removing the door and weighting it down
   --Replace the door entirely.

3. Step 3

   If it is not warped you can also check to see if the door has a square fit. If the size of the gap between the door and frame changes as it moves the door is crooked. You can remove it and shim either the top or bottom hinge with an index card to correct the problem.

4. Step 4

   If the door still seems misaligned the latch may have been installed wrong. Remove the plate and mark where the latch meets the door jamb. Move the strike plate to this point and remove any wood you need to behind it. Fill in gaps around the plate with wood filler and then paint or stain to match.