The first thing you need to do when repairing a peeling ceiling is to scrape off anything that's peeling. Using a wide putty knife will make quick work of removing the peeling paint. Though a putty knife is not overly sharp, it can gouge your ceiling. Scrape carefully to prevent this from happening. Standing on a ladder can help ease any pain in your back and make the job of scraping a bit easier. Another good idea is to wear goggles to keep the paint scrapings from getting in your eyes. Wear a mask over your mouth as well, especially if you live in an older home, where the paint might be lead-based.
Spackling your ceiling after scraping will help to even out and repair any damage to the ceiling. Apply the spackling, or sheet rock mud, to the ceiling, using a putty knife. Cover any holes or uneven spots, making the spackling as flush to the ceiling as possible. Allow the putty to dry for several hours or overnight, depending on what type you buy and how much you use. After the putty is thoroughly dry, sand it smooth.
Primer is a must if you want your ceiling repairs to look their best. Primer will help cover up uneven spots in the ceiling, especially where you may have scraped away a lot of previous paint. The primer will help the paint adhere better and will let you apply fewer coats. Using primer will also prevent the next coats of paint from peeling so quickly, if they peel at all. Primer normally dries fairly quickly, such as a few hours, but read the manufacturer's directions for exactly how long to wait before painting.
Painting your ceiling is the last step in repairing any peeling paint. Paint your ceiling with a roller as you would normally paint the walls. Use a brush to get around the edges of the ceiling, around trim and around any light or ceiling fan fixtures. Even when you've used primer, your ceiling may require two coats of paint. While most ceiling paint is white, it does not mean that you have to paint your ceiling white. You can have the paint-counter assistant add tint if you so desire. Allow the paint to dry for 24 hours before touching it and replacing ceiling fixtures.