Tighten each of the hinge screws. If the hinges have been loose for a while, the screws may be stripped or the holes too wide for the screws. Take the screws and hinges to your local hardware store and purchase the largest screws of the same style that will fit in the hinge holes. Replace the hinges and doors using the new screws.
Close the doors and look at the gap between the two doors or the door and the trim. If the doors are rubbing against one another or against the trim, remove the doors and hinges and sand either the edge of the door or the door trim until the doors open and close easily. Replace the hinges and doors.
Tighten and reposition the doorknobs and strike plate if the latch is malfunctioning. Remove the trim screws and the trim plate from around the doorknob with a Philips screwdriver. Pull the knobs off and brush any sawdust or debris from the knob hole. Replace the knobs and screws. Position the strike plate directly across from the lock bevel and tighten the screws.