Buy a small humidifier based on the volume of the space. I would adjust it for 40% to 50% humidity.
What is important is being sure that the top of the bottle is not upright. Bought a case of zin today and when I got home the wine was cork end up with the lettering right side up on the box. So I invert the carton and mark it with a large felt tip pen to show it is up. I like that many of the wineries are now shipping wine in boxes that hold the bottles horizontally which fixes the problem.