Well, in the time leading up to her next molt (signs of this include: refusing to eat, sluggish or moody behavior, balding and/or swelling around her abdomen, dull colors), be sure she’s safe. You don’t need to give her cushioning—and, in fact, it would be best if you didn’t—but do give her a solid enclosure lined with sand. Keep an eye on her and wait for her to flip over onto her back. Once she begins molting, the process may take a few days, and it’s important to remove her old skin as quickly as possible. However, be sure to wait until she casts off her old skin completely. Don’t try to assist her in molting.
Furthermore, once her skin is removed, don’t touch her. Be sure she has plenty of water and if you must feed her, only give her soft, premade foods, as opposed to live prey. (Note that it’s more likely your galvantula will have no appetite until she’s fully recovered. You should only feed her if she tries to escape her enclosure or otherwise looks as if she’s asking for food.)
And … that’s it, really. Continue giving her water and perhaps a little food every day, and in a week’s time, she’ll be back on her feet and at your side again. Galvantula really don’t need much to feel comfortable while molting, and in fact, the less you do, the more comfortable yours will be.
But either way, I cannot stress this enough: do not touch her at any point in the molting process. This is her most fragile state, and the last thing you would want to do is inadvertently injure her. Leave her be, and she will be fine.