The closet in my front hall had a folding door, as many closets do. The door was always open, and it tended to get scuffed because it was always open, so I decided to remove it and replace it with a secret door.
I started by removing the door. I measured the opening and bought 1x6s.
Next I drilled holes In the tile to place the bottom hinge, and made the basic door frame. (Drilling through tile takes forever, by the way.)
Once I had the frame the right size, I built the cabinet. (This took a while.) I then painted the frame. I ended up removing the rest of the previous trim as well, which required more repainting.
Then I attached the rest of the frame. This also took several adjustments.
I added trim and realized the hinges needed to be adjusted again, so I took it all apart and moved them to the front of the cabinet.
Finally, it was done. I touched everything up and attached the latch (which requires a magnetic key to open).