Finishing drywall involves spreading joint compound over the screw or nail holes and joints in the wall to create a smooth, flawless surface. Tape is embedded in the compound over the joints to prevent cracks. The tools and techniques are simple, but creating a smooth surface requires lots of practice. A pro can finish a wall with three coats, but beginners sometimes need to apply more. You'll need three drywall knives: a 6-inch-wide knife for the first coat, a 10-inch for the second coat, and a 12-inch for the final coat or coats. The three knives allow you to feather out the joint -- making it gradually thinner toward the edges so it blends with the wall surface when painted.
The joint compound used to finish drywall joints is commonly called mud. Use ready-mixed joint compound that comes in 5-gallon buckets. Lesser quantities are available for small jobs. Keep the bucket covered at all times so the mud won't dry out. Stir in any water that pools on the surface.
For an 8X8-foot wall, about 1-1/2 hours for the first coat, 45 minutes for each subsequent coat
Mud pan; 6-inch, 10-inch, and 12-inch drywall knives; sanding block or sponge
Spreading and smoothing joint compound
Check over wall to make sure all fasteners are sunk below surface
Joint compound, fiberglass mesh tape, paper tape (for corners), abrasives
Load some joint compound into a mud pan using a 6-inch drywall knife. Start filling the screw or nail dimples with a sweeping motion. Scrape the mud off so the dimple around the screw is filled flush to the surface. Closely spaced dimples can be filled or scraped in one motion.
After you apply the final coat of mud and it dries, the final step is to smooth the surface. You have two choices: sponging or sanding. Each method has its advantage. Sponging avoids creating dust, but sanding does a better job of making the joint flat.
To sponge, you'll need a bucket of water and a big sponge. Even better is a sponge made especially for smoothing drywall; it has a coarse mesh on one side that removes excess mud and a plain sponge on the opposite side for refining the surface. Wet the sponge and scrub the wall surface. Rinse the sponge frequently to get rid of the mud that builds up on its surface.
For an especially smooth, flat joint, you can't beat hand-sanding. This method creates lots of dust, but the results are worth it. Be sure to seal off your work area with plastic sheeting and wear a mask to avoid breathing the dust. You might be tempted to use a power sander, but don't. Power sanders fray drywall paper and blast large amounts of dust into the air.
For small jobs, a sanding block with regular sandpaper works well. For larger jobs, invest in a sanding screen (a screen mesh impregnated with abrasive) and a holder. Some holders attach to a shop-vacuum hose, which helps contain dust during sanding.