Getting your dog spayed is an important procedure, and it's fairly basic. Your dog shouldn't be in too much pain afterwards, but you want to make sure you make her as comfortable as possible.
Coming Home After Surgery
When you take your dog home, she may be too groggy or sore to stand or jump into your your car, so help her get in and out. Once you get home, take her to a soft and clean place to lay down; a familiar place such as her dog bed or even the couch is best to reduce her stress level and increase comfort. If you have other dogs, try to keep them separated so the girl who just had surgery can relax.
Food and Water
Make sure she has fresh water available. You may find that she won't eat -- the anesthesia may make her nauseous -- so offer very little kibble to see how it will affect her stomach.