Open the door for access to the hinges.
Look for looseness in any of the hinge screws that could allow the door to sag from the jamb.
Tighten loose screws firmly with a screwdriver, typically a Phillips head. Tighten the screws on the door side of the hinge as well as the jamb side.
Locate the center hinge screw on the jamb-side leaf of the top hinge.
Remove the center screw from the hinge leaf.
Replace this screw with a longer screw of about 2 or 3 inches and tighten it securely. This supports the door more firmly in the jamb.
Prop the door at the bottom with a wedge shim to give the door stability while deepening the hinge mortise. Using the wedge shim takes pressure off the hinges below the top hinge.
Remove the jamb-side top hinge leaf from the mortise in which it sits. Leave the door side of the hinge intact.
Work away a thin layer of wood within the mortise area where the hinge leaf was seated using a sharp chisel or flat-head screwdriver. Remove only enough so that the hinge seats slightly deeper than it did before.
Screw the hinge leaf back on, making sure the jamb-side of the hinge seats smoothly in the deepened mortise area. Remove the shim at the bottom of the door.