1) Feed a good quality cat food. Dry kibble is fine (and better for the cat's teeth than wet food). Read the label and make sure it has skin & coat conditioning ingredients. 2) Make sure your cat has enough water to drink. 3) Keep a humidifier going in your house in the winter time. 4) Talk to your vet about a dietary supplement. I give one of my dogs a fish oil capsule every day for her dry skin. I'm not sure it's safe for cats and the label on my bottle doesn't say. But there's probably something at your pet supply store that would work for cats.
dont bath your cat so much or make sure it has a high rich cat food. Canned tuna or a moist lamb/turkey food should do.... dont feed it "people" food. but most likely its dont bathe your cat so much :)