As you'll probably spend quite a bit of your time at the hotel wearing only a robe and slippers, you won't need to take too many belongings. Besides casual, loose-fitting clothes to change into after your pampering treatments, essential items like underwear and a toothbrush should be at the top of your packing list. Of course, if you plan to make use of the resort's pool or participate in exercise sessions, toss a swimming suit and some sports gear into your bag as well. Finally, leave the electronics in your office and take something light to read instead. It is, after all, meant to be an escape from the real world.