My aunt worked for Bath & Body Works for the past year. A couple of things she told me in order to get the best deals from them -
Always give them your phone number and email address when they ask you at checkout. This is how they track how often you come in, what kinds of things you buy, how often you use coupons. The more they see you come in, the more you will get special offers in your email and coupons sent to you. Most of the coupons they send by email can be printed out and used at the store and used online too because they give you a code. The more you shop, the more you get to save and they are often stackable with current coupons.
The coupons they give you in the store have an expiration date - however they are told at training that if a customer brings in a coupon that has just expired (within the past 10 days or so) they can tell the customer that they can make an exception and let them use the coupon. They are all encouraged to do that, so don't be worried about using an expired one if you have to.
If you have forgotten your coupon at home or if you didn't get one yet, you can often ask at the counter and they have extra coupons that they will give you to use that day. Once again they are encouraged to provide the best customer service so they should all do that. Besides they are graded by their parent company on not only sales totals but number of items sold per person - the higher their number, the better they look to management - so it's in their best interest to help you get as much stuff as you can.
If you have a bad experience at one of their stores, you can email them through their website. They will send you a nice email back and a $25 gift card to keep you as a customer. While my aunt said they saw people abuse this, it is a nice gesture on the part of the company if you have a bad experience.