Treat an aircraft door as part of the aircraft, after all it is part of the aircraft. You don't go around banging on wings and fuselages, so you shouldn't bang doors into the wing, aircraft interior or other objects. A simple inspection of an aircraft's interior or wing underside will indicate how careless most jumpers are about handling the door. After the door is pulled on jumprun, it must be stowed. Removing the door varies from plane to plane.
Some doors have latches.
Carefully move the door, sliding or rotating it, into position for stowage. Keep adequate clearance around the door. Avoid slamming the door into the interior walls, people's feet or gear, etc. Pay particular attention the top and bottom of the door, as these are the edges that will 'catch' most easily. Fasten the keepers for stowing the door.