Have a basket or a drawer with toiletries guests might have forgotten, like toothbrush and toothpaste, shampoo and conditioner, razor and shaving cream. If you want to be luxurious, throw in fancy bath salts.
Prepare a list of places to go and things to do, including a few of your favorite restaurants, so they don't have to be asking you all the time. Include directions.
Prepare to share your computer with guests in case they want to check e-mail. If you don't have a computer, be prepared to give them directions to the nearest library; most libraries have Internet access. Your guests might bring a laptop, in which case they'll need access to one of your phone jacks.
If you have a spare radio or TV/VCR, set it up in the guest room for people who can't get to sleep or who wake up early.
Fresh flowers will put you right up in that Martha Stewart category. Avoid strong-smelling flowers like Stargazer lilies, in case your guests have allergies.
A bowl of apples can look as gorgeous as fresh flowers -- and it doubles as snacks.