How to Mud the Joints of Drywall

Apply a thick layer of all-purpose drywall compound into the seam between the two pieces of drywall. Ensure the mud extends at least the width of your tape on either side of the seam so you have a good bed in which to lay the tape.

Press down a layer of drywall joint tape all along the seam, cutting it off at the floor. Smooth it by hand until it is sticking to the mud all along the joint.

Flatten the tape into the mud using a 5-inch drywall knife. Use smooth strokes and try to make the tape as flat against the drywall as you can. Take any excess compound that squishes out from under the tape as you smooth it off the wall. Work the tape until it is wrinkle-free and firmly pressed to the wall.

Run a very thin coat of compound over the top of the tape using a larger drywall knife.

Put a second coat across all the joints after the first dries. However, make sure the outside edges of your second coat extend farther than the original coat.

Allow the second coat to dry completely, then add a final coat over the top. Use the largest drywall knife you have available and feather out the edges to try and make the smoothest transition possible from the drywall itself to the mud lines. Tiny imperfections will be sanded off, but you should strive for as smooth a seam as possible just by mudding. You can try thinning your mud slightly with water for this final coat.