It is useful to have a photographic record of the works of art you have for sale. These can be A4 size, printed in colour on good quality photographic paper and placed into clear plastic folders, with the artwork visible on one side of the folder and details and the price of the work, on the other side. Remember to have a copyright stamp on all your photographed artwork and that all the works bear your signature.
Keep a notepad to hand for commission, etc., queries and contact numbers. And, remember to respond to these enquiries, Sometimes the most discreet queries come from the most important clients.