1 - DON'T use your bathroom! It may have great acoustics for singing, but for recording an audio book, not a great choice. Too much echo, unless of course you want that effect for a particular scene where the character is in a cave/tunnel. But not ideal for an entire book. You'll drive your listeners crazy.
2 - Do not have any laundry, dishwasher, or loud fans going anywhere nearby. If you've got a really good microphone, guess what it will be picked up in the background. Not acceptable to ACX requirements.
3 - Make sure the windows are closed so you don't pick up outside noises, like traffic or kids playing.
4 - Be prepared to start over... repeatedly! Things happen. You accidentally step on something, or your clothing is crinkly, etc. Where something comfortab…