Choose your fabric. A solid color or a subtle print is usually the preferred choice for upholstery, but this depends on your taste. Fabric that is easy to clean is important if you have small children at home, since they are likely to be messy eaters. If you're on a tight budget, look for a medium-weight dress cotton. Avoid leather or suede, since these fabrics are difficult for a novice to use on an upholstery project.
Remove the old cushion and chair cover. Do this as carefully as possible, so you don't rip the fabric any more than necessary. Most chairs have the seat and back cushions attached with nails or screws, but examine your chair carefully to see how it was assembled.
Cut your fabric using the old chair cover as a pattern. Use sewing scissors made for cutting fabric; regular household scissors will make it hard to get a clean cut.
Staple the fabric back onto the cushion using a heavy-duty upholstery stapler or a nail gun. The fabric needs to be pulled tightly to avoid creases. If possible, have another person help you with this step.
Add decorative upholstery tacks if desired. Tacks can be purchased at any store that sells upholstery supplies. You generally won't be able to reuse the tacks from the original upholstery job, since it's impossible to pull them out without bending them.
Reattach the newly reupholstered chair back. Once you're satisfied with the result, repeat the process on the rest of the chairs in your dining set.