Keywords are the words you use to search on the Internet. Be sure to use as many popular keywords as you can in your descriptions. Used Spa Lot is crawled by all the major search engines so the better the description the better your chances for your specific listing to get picked up.
Examples:
Good - Used Hot Tub Cover for Sundance Spa Optima or Cameo
Not so good - Used Spa Cover cheep – make offer...
If someone searches Used Hot Tub Cover Sundance, the top example pickups up considerably more search terms even though the second version sounds like a better deal.
By following these few important steps, you will maximize your chances to sell your product and put money in your pocket.
Good Luck and Good Selling...