73 duster drivers door won't close

Could be a couple different things. Striker adjustment to far in or out. Looking for 2 clicks, 1st is safety second is door fully latched. Is it springy when you go to close it? It might be too close to to the body. The hinges on the door side, 2 bolts upper and 2 lower, have adjustment room to move it in or out. Loosen all 4 and the door drop to the bottom of it's adjustment. Sometimes it only takes as small amount. Adjust one hinge at a time, loosen, bump a skosh, tighten, and go to the bottom hinge. If you can't get it within adjustments need to look carefully at the a-pillar. Faulty latch, gaskets binding, top of glass laying in too far. Like Rumble said pics are good, and a little more info.