The built-in wardrobe described here is designed for shoes (a wardshoe?), so it's a bit shallower than the average wardrobe, and it's filled with shelves rather than a clothes rail. However, the construction is pretty much the same as other built-in wardrobes I've made - this is just the only one I thought to document. It took an afternoon to build, then plastering took a week as did painting.
Step 1: Design
The room is wired with a light switch on each side. I planned to remove the one that would be hidden in the wardrobe and replace it with a receptacle, so we could add a small heater if needed in the winter months.
Four shelves 400 mm apart, plus the floor, would give us separate footwear storage for each member of the family (5). I also added a half-depth shelf 400 mm higher (above the level of the door) for some additional storage.