My drivers door had a big dent, like someone had whacked it with a dull axe. It was ugly. So, I found another door and was going to use it. I painted it and everything BUT someone had filled in the door lock. I didn't really like that...but thought I could live with it. After much thought I decided I would try to fix my existing door. The idea was if the door on the car came out crappy, I at least had the back up door. The door on the car actually turned out real nice. I knocked the dent out as flat as I could, used a little filler, a lot of sanding then painted it.
In this picture you can see the dent it's just below and in front of the door handle
Her is the progress of the door pictures
Base coat
and cleared