Place your melamine laminate bookcase on a drop cloth to protect the area where you will be painting.
Remove the shelves from the bookcase if possible.
Use an orbital sander with a 150-grit disk to sand the entire bookcase and shelves. Use 150-grit sandpaper sheets to reach any spots that the orbital sander cannot reach. Wipe the bookcase down with a tack cloth to remove any excess dust.
Pour latex primer into a paint tray, and use a roller to apply a coat of primer over the entire bookcase and shelves. Allow the primer to dry completely.
Wash your roller and paint tray out while you are waiting for the primer to dry.
Stir the latex paint with a stir stick to combine the paint well.
Pour latex paint into the paint tray, and paint the bookcase with a roller and paintbrush. Allow the first coat to dry, and then apply a second coat if needed. Allow the paint to dry.
Place the shelves back into the bookcase. Use a paintbrush to touch up any scratches that may have appeared during reassembly.