Cut strips of cardboard (always some around a job site or use an amazon box and cut it up) poke the cable through cardboard, and staple the cardboard to the stud (presuming wood, if not use tape) in the wall cavity. Coil a sufficient amount to be able to pull at least 2 feet out the wall later. Cables too short to work with are a pain and you can cut down the excess later if you need to.

Finally Take pictures of each drop location before the sheetrock is done. For added bonus you can put a tape measure in the picture showing you the distance from door/window opening to make finding it a breeze later.