When choosing a potato you want to make sure the potato is firm. You want to stay away from any potato that has a strong unpleasant odor, if the skin of the potato is shriveled or sprouting, or if the potato has gone soft or wrinkly. These are all signs that the potato is no good.
Do not wash potatoes until ready to use, once ready to use take a small kitchen brush and while running the potato under cool water brush off any remaining dirt that may still be on the potato.
Store the Potatoes in a cool, dark and well ventilated place. They will keep for up to 2 weeks this way.