Write an article based on this "Check the wall. Remove the existing door, if applicable."
The last thing you want to do is to tear a hole into your wall only to find that it's not feasible to put a door there. Before you go about drilling and tearing down, check for the following things:  Check if there's enough room in the wall. You need just over twice the width of the door (so it can hide). Check if the wall is load-bearing or just a partition. If it is load bearing, you'll need a new header and a means of temporary support while the door is being worked on. Check for wiring or plumbing. A wall with pipes in it is not a good place to put a door. Wiring can be easily detected with a cheap voltage sensor. If you're replacing a door with a pocket door, you'll need to get rid of the existing door. Start with removing the molding and, with a reciprocating saw blade, cut the shims. When the nails are cut, you can remove the door frame. Door jambs aren't nailed against the studs in the wall – they're just spaced with wooden shims.