You can adjust closing linkage if you still have it and connected to handle on top of dash.That will put more pull on door, but make releasing handle a little stiffer, depending on how much adjustment it takes to make it seal. If linkage has been removed and latch is what holds it closed like a house door, have someone hold a piece of 4x4 between door and body at latch area. Use a 2x4 on edge at bottom and try to pry door closed. You will need to experiment to get what you need. Just keep checking it. You may need something like a 6x6 instead of a 4x4, just not so heavy it can't be held there. Removing inner trim panel can help if not too inconvenient. If you feel nervous about this, check with an older body shop about doing this or have them do it.
