Replace outside lights with higher wattage bulbs. Remove stored items around house, pool and garage. Prepare and have handy Property Disclosures and Lead Disclosure. Offer compensation to agents at a fair market price, and make this known. Have someone available to answer the phone when a buyer calls, or at least have an answering machine message with some details on your home prepared.
Return calls promptly and courteously.
Be reasonable with showing times. Many buyers work during the day, and will only be able to view your home in the evening or on weekends. Have flyers detailing the features of your home, including room dimensions, handy. Photos keep the home fresh in the minds of buyers when they go home. Keep track of who views your home and follow up with them after they leave.