Zipper problems? Soap.
Juliette Binoche is a French actress, artist, and dancer. She has appeared in more than sixty feature films and has been the recipient of numerous accolades, including an Academy Award, a British Academy Film Award, and a César Award. In the photo below is her wearing a white dress with a zipper at the back as she poses in the red carpet.
One of the most common with these garments having a zipper is when it gets stuck. No matter how much you tug at it, there’s no hope it’ll ever go up. So first things first: Don’t yank on it. Period. Second thing? Get some bar soap. This kind of lubricates the zipper, allowing you to pull the zipper up. Banana peel or wax of a crayon works, too.