Cover your work surface with newspaper or a dropcloth. Turn your table over to rest your tabletop on the work surface.
Remove any peeling or chipping paint, using a scraper. Smooth out uneven paint by sanding it with 150-grit sandpaper. Add a slight tooth to glossy, painted surfaces with 220-grit sandpaper. Remove dust from your table legs with a tackcloth.
Cut plastic sheeting to cover the underside of your tabletop and fit around the table legs, using scissors. Tape where the table legs meet the tabletop.
Prime the legs with latex or oil-based primer. Oil-based primer is more durable, but has a longer drying time and stronger paint fumes. Apply the primer with a brush, watching for dripping or pooling primer as you go. Allow the primer to dry, letting oil-based primer dry overnight.
Wash a brush used with latex primer with soap and water. Use mineral spirits to remove oil-based primer from a paintbrush.
Apply latex paint over latex primer and oil-based paint over oil-based primer for the best adhesion. Apply two smooth, even coats of semi-gloss paint to the legs of your table. Smooth out thick paint with your brush. Allow the semi-gloss paint to dry between coats, following the directions on the paint can for recoat times.
Wash your brush. Remove the tape and plastic sheeting. Allow the paint to cure completely before using the table.