Scoop joint compound out of its bucket using a 6-inch drywall knife and place it in a drywall pan. Fill the pan halfway to make it more manageable.
Place a bead of joint compound on the edge of the knife about an inch wide. Use the side of the pan to scrape off excess compound from the knife.
Smooth the joint compound over the inferior or blemished part of the drywall. Use the drywall knife at a low angle relative to the wall to spread the compound, and at a larger angle to remove excess compound. Use long, even movements to create a continuous, smooth finish. Let the joint compound dry for 24 hours, or longer if there is high humidity.
Sand the repaired area using a drywall sanding screen. Lightly sand the area to remove ridges and bumps. The surface can be painted or wallpapered per your preference.