Not sure if anybody has a different method or already do this, but I figured I would share just in case anyone else needed a method to keep track of everything. A book and quill is cheap enough to make and you can use it to keep track of where everything in your world is in case you decide to return to it or simply leave a world for awhile and then decide to come back. I started doing this about a month ago and it works wonders for both the Nether and the Overworld.