I love that pattern and have a few pieces myself. Jewel Tea Autumn Leaf, often referred to as Autumn Harvest, is most valuable if it's in pristine condition. That means no wear marks, no cracks, no dings. As there were copies made, make sure that your dishware is labeled with the Mary Dunbar stamp on the bottom to prove authenticity.
The Jewel Tea company sold home goods door to door in the early 1900s. It started when Frank Vernon Skiff thought it was a good idea to sell fresh ground coffee from a wagon in 1899. By 1933, when the world was in the grip of the Great Depression, homemakers could buy Autumn Leaf piece by piece from a salesman who cruised neighborhoods in a truck.
Do not place your dishware in a microwave. Do not clean old dishware in a dishwasher; clean them by hand. If you stack pieces, place a paper towel in between each dish.
I can't tell you how to sell your dishware. That is up to you. But you can find lots of information on the product on the Jewel Tea Collectables site, or at Kovels, Replacements, or Ruby Lane. If you sell through a dealer, let the dealer decide whether or not to sell your dishes all together as he or she will understand the local market.