Things You'll Need
Seam or joint tape
Drywall mud, or joint compound, is used to smooth joints in walls and ceilings before they're painted or wallpapered. When it's properly applied the joints between sheets of drywall are invisible. Drywall mud is also used to smooth out imperfections in walls and ceilings and to fill holes. It can be used to conceal the grooves in paneling when you paint it. Applying drywall mud is a simple technique but it takes some practice to master.
Use a drywall knife to apply a thin layer of mud along joints in the drywall. Skip this step if you're using adhesive tape.
Smooth seam tape over the layer of mud on the joints. Press it down with a drywall knife to remove air bubbles. If you're using adhesive tape, wet the tape and apply it to the joint. Make sure the tape is perfectly smooth.
Allow the mud to dry for twenty-four hours.
Smooth the surface by sanding over the joint tape. Remove any pieces of tape that stick out with scissors or a utility knife.
Apply another thin layer of drywall mud about six inches wide. Smooth or feather the edges to to blend into the wall.
Allow the mud to dry and sand it smooth again.
Use paint primer if you're going to paint. Wallpaper can be applied directly over the drywall without further preparation.
If the tape puckers or doesn't stick, pull it off the wall, sand the area and start over again. Sanding will create lots of dust particles. Protect furniture with dropcloths and close off other rooms. Simply sand drywall mud smooth after it dries if you're using it to fill holes or cracks.
Clean up spills quickly. Once the mud dries it's hard to remove.