While drywall may appear to be a strong solid surface, the material alone isn't capable of withstanding the pressure brought about from the weight of many larger wall-mounted televisions. Mounted directly to drywall, the TV can break the material posing a danger to both the wall, as well as anyone nearby. To avoid this, locate and use the wall studs behind your drywall as extra support. By mounting through the drywall into the studs beneath you'll have the structural strength you need to bear the weight of your TV. This strength will then enable you to hang your TV on the drywall safely and securely.
Obtain a VESA compatible wall mounting kit that's rated for the weight of your TV.
Locate the wall studs behind the drywall in the area where you intend to hang the TV using a stud finder. Run the stud finder over the drywall, watching the indicators for the presence of studs. Mark the centre of the studs with a piece of chalk where the indicator is strongest.
Install the mounting bracket to the rear of your TV using the screws included with the mounting kit. Center the mount on the TV. Secure the mount by placing the screws through the mount holes into the aligned mounting holes in the rear of the television set.
Place the wall mount onto the drywall, using a carpenter's level to ensure it's level to the floor. Mark the position of the mount by placing a pencil mark through the mounting holes onto the surface of the wall. Position the mount so that it's placed over as many rows of studs in the wall as possible with the screw holes in the mount landing squarely on the centre of the studs. Lower the mount to the ground.
Drill anchor holes through the marks placed onto the drywall for the mounting screws using an electric drill. Drill straight through the drywall into the studs, creating pilot holes for the screws.
Secure the mount into place using the anchor screws. Hold the mount against the wall, with the mount holes aligned with those that you drilled. Place the anchors into the pilot holes and screw them tightly against the mount using a socket wrench.
Lift the TV to the mount, using a helper for heavier televisions. Slide the mounting bracket onto the wall mount and then lock the television in place with the mount's safety tabs.
Take note of the power and video connectors in your LCD TV to prevent the need for searching their locations after mounting.