Sand the surface with 220-grit sandpaper to prepare it for paint. You can do this by hand or with an electric sander.
Wipe the surface with a tack cloth to remove sanding dust.
Apply a coat of latex primer if you are antiquing something dark. Allow the primer to dry, then sand it with the 220-grit sandpaper. If primer is not needed, skip this step.
Apply a coat of latex paint onto the surface and allow it to dry for 24 hours. This will be the color that shows through the surface coat as aged portions.
Brush a thin coat of paste wax onto the areas that you want to appear aged. These areas are usually those that see the most use, such as the arms of chairs and the ends of bookcase shelves.
Allow the paste wax to dry for one hour.
Paint the surface with latex paint in your surface coat color. Allow the paint to dry overnight.
Lightly sand the waxed areas using 150-grit sandpaper. This will remove the surface coat, allowing the other paint to show through.
Apply a coat of protective sealant when you are happy with the finish.