Clear out the room as much as possible. Anything you cannot take out can be placed in the center of the room and covered with plastic or drop cloths..
Scrape and sand any loose or flaky paint with paint scrapers or sand paper. If necessary, sand to the bare surface until the surface is smooth.
Using a putty knife and spackle, fill in all holes, cracks and imperfections. After the spackle has dried, sand again to smooth the surface. Repeat as necessary.
Wipe down walls and trim with rags to remove dust and loose particles. Dust and vacuum up any debris that remains.
Remove all outlet plates, switch plates and air vent covers. Using FrogTape Multi-Surface painters tape, mask around molding, windows and doors and any switch or fixture that wasn’t removed (Use caution when masking over or around outlets). Apply FrogTape so the edge is flush against the surface to be painted and then press down along the tape edge with a putty knife to help ensure a good seal.
Cover your floor with drop cloths or plastic to protect it from any paint splatter.